July / 2012

July

/12

Medical Devices • Aspheres • Spectroscopy

Aspheres Deal with Bigger Deviations

Electronics Augments Modern Process Control Spectroscopy

All-Fiber ProbesNew Promise for MedicalImaging Applications

712PScover_Layout 1 6/25/12 2:36 PM Page 1

712_LightworksOptics_PgCVR2_Layout 1 6/25/12 3:59 PM Page CVR2

712_SRS_PhotonCount_Pg3_Layout 1 6/25/12 4:01 PM Page 3

July 2012

t TABLE OF CONTENTS

20 | TECH NEWSPhotonics Spectra editors curate the most significant photonics research and technology headlines of the month – and take you deeper inside the news. Featured stories include:

• Single nanomaterial yields a laser rainbow • Coupled lasers cancel each other out• Solar cell-like implant stimulates optic nerve

34 | FASTTRACKBusiness and Markets

• Software gives photonics designers more power• LME 2012 expands educational offerings

41 | GREENLIGHTLED-like solar cell absorbs, emits light

10 | EDITORIAL

12 | LETTERS

82 | PEREGRINATIONSUncooled IR camera reveals mysteries of space

NEWS & ANALYSIS

70 | BRIGHT IDEAS79 | HAPPENINGS81 | ADVERTISER INDEX

DEPARTMENTS

THE COVERJean-Michel Pelaprat and Dr. Baishi Wangof Vytran LLC discuss optical fiber probesfor medical imaging applications, begin-ning on p. 42. A schematic of the filamentfusion process is illustrated. Design bySenior Art Director Lisa N. Comstock.

20

82

Photonics Spectra July 20124

COLUMNS

712Contents_Layout 1 6/25/12 4:32 PM Page 4

PHOTONICS: The technology of generating and harnessing light and other forms of radiantenergy whose quantum unit is the photon. The range of applications of photonics extendsfrom energy generation to detection to communications and information processing.

Volume 46 Issue 7

www.photonics.com

42 | ALL-FIBER PROBES HOLD PROMISE FOR MEDICAL IMAGING APPLICATIONSby Jean-Michel Pelaprat and Dr. Baishi Wang, Vytran LLC Designs made possible by filament fusion technology have found applications in medical imaging such as 1- and 2-D optical coherence tomography.

46 | NANOSCALE BIOMATERIALS REQUIRE CLOSE OBSERVATIONby Lynn Savage, Features EditorDeep-imaging microscopy could advance the use of polyurethane-based “nanohybrids”in replacement bones and blood vessels.

52 | DPSS LASERS GIVE MEDICAL DEVICE MANUFACTURING AN EDGEby Jim Bovatsek, Jürgen Niederhofer and Dr. Rajesh S. Patel, Spectra-PhysicsAs medical devices continue to shrink, these solid-state lasers offer a versatile alternative to CO2 and excimer.

55 | BEAM PROFILING HELPS MAKE MEDICAL DEVICES BETTERby John McCauley, Ophir-Spiricon The range of information provided by laser measurement products ensures the consistency and precision of the machine or process.

58 | ELECTRONICS AUGMENTS MODERN PROCESS CONTROL SPECTROSCOPYby Gert Noll, Tec5USA Inc., and Mathias Holzapfel, Tec5 AG In process control, the detector array and readout electronics are key; ideally, these are combined with a large signal-to-noise ratio and high dynamic range.

62 | ASPHERES DEAL WITH BIGGER DEVIATIONSby Hank Hogan, Contributing EditorAs aspheres with deviations up to 800 µm have become common and manufacturingruns have become smaller, metrology tools and techniques have evolved to keep up.

PHOTONICS SPECTRA ISSN-0731-1230, (USPS 448870) ISPUBLISHED MONTHLY BY Laurin Publishing Co. Inc., BerkshireCommon, PO Box 4949, Pittsfield, MA 01202, +1 (413) 499-0514; fax: +1 (413) 442-3180; e-mail: photonics@photonics.com. TITLE reg. in US Library of Congress. Copyright ® 2012by Laurin Publishing Co. Inc. All rights reserved. Copies of Pho-tonics Spectra on microfilm are available from University Mi-crofilm, 300 North Zeeb Road, Ann Arbor, MI 48103. PhotonicsSpectra articles are indexed in the Engineering Index. POST-MASTER: Send form 3579 to Photonics Spectra, Berkshire Com-mon, PO Box 4949, Pittsfield, MA 01202. Periodicals postagepaid at Pittsfield, MA, and at additional mailing offices. CIRCU-LATION POLICY: Photonics Spectra is distributed withoutcharge to qualified scientists, engineers, technicians, and man-agement personnel. Eligibility requests must be returned withyour business card or organization’s letterhead. Rates for oth-ers as follows: $122 per year, prepaid. Overseas postage: $28surface mail, $108 airmail per year. Inquire for multiyear sub-scription rates. Publisher reserves the right to refuse nonquali-fied subscriptions. ARTICLES FOR PUBLICATION: Scientists,engineers, educators, technical executives and technical writersare invited to contribute articles on the optical, laser, fiber optic,electro-optical, imaging, optoelectronics and related fields.Communications regarding the editorial content of PhotonicsSpectra should be addressed to the managing editor. Con-tributed statements and opinions expressed in Photonics Spec-tra are t hose of the contributors – the publisher assumes noresponsibility for them.

62

58

FEATURES

Photonics Spectra July 2012 5

712Contents_Layout 1 6/25/12 4:33 PM Page 5

Photonics Spectra July 2012

Group Publisher Karen A. Newman

Editorial Staff

Managing Editor Laura S. MarshallSenior Editor Melinda A. Rose

Features Editor Lynn M. SavageEditors Caren B. Les

Ashley N. PaddockCopy Editors Judith E. Storie

Patricia A. Vincent Margaret W. Bushee

Contributing Editors Hank HoganGary BoasMarie Freebody

Creative Staff

Senior Art Director Lisa N. ComstockBioPhotonics Art Director Suzanne L. Schmidt

Designer Janice R. Tynan

Director of Publishing Operations Kathleen A. Alibozek

Electronic Media Staff

Director Charley RoseMultimedia Services & Marketing

Web Development Team Leader Brian L. LeMireWeb Developers Alan W. Shepherd

Brian A. Bilodeau

Editorial Offices

2 South Street, PO Box 4949 Pittsfield, MA 01202-4949

+1 (413) 499-0514; fax: +1 (413) 442-3180www.photonics.com

Laurin Publishing has additional editorial offices throughout the world. News re leases should be directed to our main office. If you would like an editor to contact you, please notify us at the main office, and we will put you in touch with the editorial office nearest you.

Editorial email: editorial@photonics.comAd Sales email: advertising@photonics.com

More Than 95,000 Distributed Internationally

www.photonics.com

Association ofBusiness Publishers

712Masthead_Layout 1 6/25/12 3:36 PM Page 6

Security, unmanned vehicles, retail analytics and a range of other applications are about

to change. Introducing Tamarisk®

320, the first 320 x 240 VOx microbolometer camera of

its kind. Combining 17 μm pixel pitch technology with our patented, advanced absorber

design, the Tamarisk®

320 delivers unmatched thermal image quality in a package weighing

as little as 30 grams, occupying under 25 cm3 and drawing as little as 750 mW of power.

Which means it’s incredibly easy to integrate the Tamarisk®

320 into virtually any platform.

The Size, Weight And Power Leader. That’s Go To.

drsinfrared.com/Tamarisk

The Tamarisk®

320 Thermal Camera Actual Size

THE INCREDIBLY TINY THERMAL CAMERA. WHERE WILL YOU USE IT?

712_DRSTechnology_Pg7_Layout 1 6/25/12 4:02 PM Page 7

Isolate... Intensify...Q-SWITCHYour innovation inspires us to create photonic technologies that empower and differentiate.

Make Qioptiq your source for high-performance electro- and magneto-optics. Our extensive line of Pockels Cells, Faraday Isolators and Laser Modulators ensure you of exacting beam modification and control. Specify precision... Discover Qioptiq.

3

800-429-0257 +44 2380 744 500 +49 551 69 35-0 +65 64 99 77 66

BOOTH 729San Diego, CA USAAUG 14-16, 2012

Photonics Spectra July 2012

www.photonics.com

Corporate Staff

Chairman/Founder Teddi C. LaurinPresident Thomas F. Laurin

Controller Mollie M. ArmstrongAccounting Manager Lynne M. Lemanski

Accounts Receivable Manager Mary C. GniadekBusiness Manager Elaine M. Filiault

Human Resources Coordinator Carol J. Atwater

Business Staff

Director of Sales Ken TyburskiAssociate Director Rebecca L. Pontier

Advertising Production Coordinator Kristina A. LaurinTrade Show Coordinator Allison M. Mikaniewicz

Marketing Project Manager Krista D. ZanolliComputer Systems Manager Deborah J. Lindsey

Computer Assistant Angel L. MartinezCirculation Manager Heidi L. Miller

Assistant Circulation Manager Melissa J. LiebenowCirculation Assistants Alice M. White

Kimberly M. LaFleur Theresa A. Horn

Subscriptions Janice L. ButlerTraffic Manager Daniel P. Weslowski

Advertising Offices

Main Office 2 South Street, PO Box 4949Pittsfield, MA 01202-4949+1 (413) 499-0514Fax: +1 (413) 443-0472 advertising@photonics.com

Austria, Germany Olaf Kortenhoff& Liechtenstein Gartenstraße 46

53721 Siegburg, Germany+49 2241 1684777Fax: +49 2241 1684776olaf.kortenhoff@photonics.com

Japan Scott ShibasakiThe Optronics Co. Ltd.Sanken Bldg., 5-5 Shin OgawamachiShinjuku-ku, Tokyo 162-0814, Japan+81 3 5225 6614Fax: +81 3 5229 7253s_shiba@optronics.co.jp

China Hans Zhong/Hai Yan QinShenzhen Fortune Technologies Ltd.3-7E, Di Jing Feng, Moi City, BujiShenzhen, China 518112+86 755 2872 6973Fax: +86 755 8474 4362hans.zhong@yahoo.com.cn

For individual advertising contacts’ information,view listings next to advertiser index.

The editors make every reasonable effort to verify the information published, butLaurin Publishing assumes no responsibility for the validity of any manufacturer’s,nonprofit organization’s or individual’s claims or statements. Laurin Publishing doesnot assume and hereby disclaims any liability to any person for any loss or dam-age caused by errors or omissions in the material contained herein, regardless ofwhether such errors result from negligence, accident or any other cause whatsoever.

712Masthead_Layout 1 6/25/12 3:36 PM Page 8

712_Hamamatsu_Pg9_Layout 1 6/25/12 4:02 PM Page 9

e EDITORIAL COMMENT

Keep conditions right for inventionHigh achievement always takes place in the framework of high expectation. – Charles F. Kettering, inventor of the electric starter

Contemplating the many contributions of Elias Snitzer, whose pioneering work in glass lasers helped bring about a communications revolution, made me wonderabout the atmosphere prevalent in his day that supported such discovery. Were

expectations high? Was there a sense of competition? Was invention rewarded and protected?

Snitzer, who died May 21 at the age of 87, had a four-decades-long career as an engineerand educator. Known as the father of the glass laser, he demonstrated the first Nd:glasslaser in 1961, hot on the heels of Theodore H. Maiman’s report of the first crystalline laserbased on ruby. His contributions made possible the fiber optics technology on which the Internet and other communications systems operate.

Laser “firsts” dropped like boom-era babies in the years right after Charles Townes andArthur Schawlow published on the concept in 1958. No doubt excitement and healthy competition, not to mention forward thinkers with markets in mind, fueled the many advances made during that time.

Decades before Snitzer and his laser contemporaries found success, Charles Kettering waschanging the world through improved automobile operation and safety with his ground-breaking work at Delco and GM Research. In roughly the same era in which Einstein de-fined stimulated emission, laying the groundwork for the laser, Kettering was revolutioniz-ing transportation. As with Kettering, Snitzer was inventive throughout his long career.

With degrees in electrical engineering from Tufts University and in physics from the University of Chicago, Snitzer began his career at Honeywell Industrial Instruments Div.,working on thermal detector technology. He taught at Lowell (Mass.) Technological Insti-tute before joining American Optical, where he began his work in optical fibers and lasers.

At Polaroid Corp. in the 1980s, he and his team first demonstrated the double-clad fiberlaser, thereby facilitating optical pumping of fiber lasers and amplifiers. After Polaroid, he worked at Rutgers University, where he continued to teach and to research fiber laseramplifiers, glass and fiber Bragg gratings until his retirement in 2001, according to anOSA release.

At the end of the day, patent laws mean nothing without curious and determined inventorssuch as Kettering and Snitzer. “Dr. Snitzer made a huge difference to our field, and hiswork has contributed to and influenced our world in profound ways,” said SPIE CEO Eugene Arthurs in a statement following Snitzer’s death. His influence will no doubt befelt for some time to come.

Charles Kettering reportedly said, “My interest is in the future, because I am going tospend the rest of my life there.” I don’t know how much Snitzer and the other laser pioneers thought about the future and the influence of their work, but they certainlywatched both unfold around them. Perhaps we can best honor Snitzer’s memory by maintaining optimal conditions for discovery and invention, and in so doing, continue to ensure a tomorrow in which people will want to spend their lives.

Editorial Advisory Board

Dr. Robert R. AlfanoCity College of New York

Walter BurgessPower Technology Inc.

Dr. Michael J. CumboIDEX Optics & Photonics

Dr. Timothy DayDaylight Solutions

Dr. Donal DenvirAndor Technology PLC

Patrick L. EdsellAvanex Corp.

Dr. Stephen D. FantoneOptikos Corp.

Randy HeylerOndax Inc.

Dr. Michael HoukBristol Instruments Inc.

Dr. Kenneth J. KaufmannHamamatsu Corp.

Brian LulaPI (Physik Instrumente) LP

Eliezer ManorShirat Enterprises Ltd., Israel

Shinji NiikuraCoherent Japan Inc.

Dr. Morio Onoeprofessor emeritus, University of Tokyo

Dr. William PlummerWTP Optics

Dr. Richard C. PowellUniversity of Arizona

Dr. Ryszard S. RomaniukWarsaw University of Technology, Poland

Samuel P. SadouletEdmund Optics

Dr. Steve ShengTelesis Technologies Inc.

William H. ShinerIPG Photonics Corp.

John M. StackZygo Corp.

Dr. Albert J.P. TheuwissenHarvest Imaging/Delft University

of Technology, Belgium

Kyle VoosenNational Instruments Corp.

10 Photonics Spectra July 2012

karen.newman@photonics.com

712Editorial_Layout 1 6/25/12 3:52 PM Page 10

712_Trumpf_Pg11_Layout 1 6/25/12 4:03 PM Page 11

l LETTERS

Something in the airThe recent article on airglow (“The NightGlows Brighter in the Near-IR,” April2012) contains misleading statements anda generally sloppy treatment of radiomet-ric units of measure. Some behind-the-scenes math by the authors and morescrupulous editing by Photonics Spectrawould have gone a long way to makingthis article more correct and meaningful.Instead, it reads like a marketing “puffpiece.” Ironically, the article tends todownplay the signal-to-noise advantage of InGaAs and visible-enhanced InGaAssensors for airglow-only imaging scenar-ios as compared with silicon sensors usedin the same conditions. InGaAs and visi-ble-enhanced InGaAs cameras are clearlysuperior under certain conditions, but thearticle simply asserts this with minimalsupporting data.

The article should have related the ob-served airglow sterance values for airglowto signal-to-noise ratios for the Xenics InGaAs camera with a typical short-wave-length infrared (SWIR) lens f/stop setting,the appropriate pixel active area, readnoise and dark current, and a practicalframe rate (30 Hz comes to mind). Thesame calculation also should have beenperformed for a low-light silicon sensor,such as an sCMOS or electron-multiplyingCCD camera, and, possibly, Gen 3 night-vision goggles based on a microchannelplate image intensifier. Without this expo-sition, the reader is left wondering justhow useful the airglow is for night visionand which technology has the advantage.

The answer is that InGaAs cameras arevery useful for this application, providedthey have low enough noise-equivalent irradiance (NEI). This NEI requirementgenerally translates to a need for a noiselevel of less than 50 e� in hopes of imag-ing with airglow at a reasonable signal-to-noise ratio with low f number optics at30-Hz frame rates. By comparison, experi-ence tells us that the noise floor for siliconcameras can be down around 1 to 2 e� perpixel per frame at 30-Hz frame rates, butthat isn’t enough to give good 30-Hz im-agery from airglow alone – there is simplynot enough no-moon airglow signal in thevisible band and near-IR band out to thesilicon cutoff around 1.1 μm.

It is simply untrue that the spectral irra-diance is “several times stronger” in the900- to 1700-nm band relative to the visi-ble band, as the second sentence of the article asserts. The spectral radiant ster-

ance is much stronger in the InGaAs bandrelative to the visible band. By careful examination of curve 1 in Figure 1 in thearticle, one can see that the spectral radi-ant sterance at the peak of the curve is actually about 40 times greater than thespectral radiant sterance at 0.510 μm,where the scotopic (low light) response ofthe eye peaks. No one would consider thefactor 40 equivalent to “several.” Even atthe peak of the no-moon airglow curve inthe visible band at 0.577 μm (emission resulting from monoatomic oxygen), thepeak SWIR signal at 1.6 μm is still 18times greater. It appears that the graph in Figure 1 was misinterpreted as having a linear Y-axis, rather than a log base 10 axis.

I am not even sure why the authorschose the term “spectral irradiance” to describe the airglow radiation in a givenwaveband, since spectral irradiance is afunction of wavelength, and irradiance isthe radiant sterance integrated over the effective solid angle. The irradiance on asurface illuminated by airglow will varywith the angle between the illuminatedsurface and the sky zenith. Radiometricunits are being bandied about here with no clarification or exposition.

Using the data from Figure 1, curve 1,my calculations show that the effectivephoton sterance for an InGaAs camera is180 times the effective photon sterance forlow-light (scotopic) human vision. Again,this ratio is quite a bit more than “sev-eral.” That is the point of using SWIR imagers to exploit the airglow radiation –there is 180 times more total usable signal

available to an InGaAs camera relative to the total signal usable by the unaidedhuman eye and 22 times more signalavailable relative to a monochrome siliconsensor. My calculations also involved con-volving both the photon spectral responsecurve of a typical InGaAs sensor, a typicalsilicon sensor and the low-light human eye luminous response curve with thespectral radiant sterance curve in Figure 1converted to photon units. These convolu-tions were then integrated over the appro-priate passbands. Flir’s VisGaAs detectorsgive similar results to standard InGaAs because almost all the airglow signal is at 0.9 μm and above.

The values I calculated are based oncurve 1, but the airglow intensity is vari-able with cloud cover, solar activity andlatitude, and that all should have beennoted in the article. A survey of other air-glow measurements yields various valuesof photon sterance for an InGaAs cameraon the order of 1010 photons per secondper square centimeter per steradian. This is comparable to results using the Vatsiacurve 1 data. It would be useful to havegiven a range of sterance values one canexpect based on airglow measurements inthe literature and, as mentioned earlier, tohave made some attempt to relate theseobserved sterance values to signal-to-noiseratios for the Xenics NV camera and othercompeting low-light electro-optics tech-nologies.

The careless treatment of radiometricunits of measure manifests itself in severalother places in the article. The Y-axis inFigure 1 in the article has incorrect units,

12 Photonics Spectra July 2012

Figure 1. Spectral photon sterance: Vatsia’s 1972 no-moon nightglow, curve 1.

712Letters_Layout 1 6/25/12 3:44 PM Page 12

Features

1460 fps @ 1920 x 1080 pixel (HD)

1107 fps @ 1920 x 1440 pixel (HD+)

12 bit dynamic range

pixel size 11μm x 11μm

image memory up to 36GB

multiple trigger options

smart battery control

Applications

short time physics

plasma imaging

materials testing

biomechanics research

spray imaging

combustion imaging

TV / broadcasting

pco.dimax HD/HD+ high speed CMOS camera system

712_PCOTech_Dimax_Pg13_Layout 1 6/25/12 4:03 PM Page 13

as it did in the original paper by Vatsia et al. The units should be spectral radiantsterance, not radiant sterance, because theVatsia group measured the radiation fromthe sky with a Fourier transform spectrora-diometer as a function of wavelength. Thefour curves are thus plots of the measuredspectral radiant sterance for four differentmoon illumination levels. The radiant ster-ance (also called power radiance) is the integral of the spectral radiant sterancecurve over a particular passband. It is thein-band radiation available to be collectedat the optical aperture of a camera. Thenumber of photoelectrons generated bythis radiation depends on the absolutespectral response or quantum efficiencycurve of the detector/lens combination,which is then convolved with the spectralradiant sterance curve as well as the pixelactive area, the lens f number and opticstransmission.

Those of us in the infrared camera fieldwho are doing modeling of airglow imag-ing routinely convert historical measure-ments such as Figure 1 into “photons persecond” units instead of their original

“watts” power units. We thus end up withspectral photon sterance. Photon units area more logical set of units to use for theseairglow calculations because the detectorscited in Figure 2 in the article are all pho-ton detectors, not power detectors. Figure2 in the article has the spectral responsesof the detectors in power units. If I hadwritten the article, I would have first con-verted the curves in Figure 1 to photonunits and then presented the spectral re-sponses in photon units in Figure 2. TheInGaAs spectral response curve is nearlyflat in photon units, making it reasonableto describe it with a “square band” ap-proximation; i.e., integrating the spectralphoton sterance from 900 to 1700 nm.

Another quibble with Figure 2 is that it has an airglow curve, but the second Y-axis is not labeled with radiometricunits. I’m assuming the correct Y-axisunits for that curve are W/cm2/sr/μm because the peak value at 1.6 μm is 100times greater than the peak value in theVatsia data in Figure 1, curve 1. The factorof 100 would come from the differencebetween using 10 nm and 1 μm in the unit

denominator. Labeling the second axis ofFigure 3 with the right units would havebeen a good idea to avoid confusion withthe Y-axis units in Figure 1.

The article asserts that the radiationdensities of moonlight and airglow arecomparable. What is meant by radiationdensity? Do the authors mean the spectralradiant sterance? Moonlight and airgloware indeed comparable in power units(spectral radiant sterance), but not in pho-ton units, which, again, are more appropri-ate for calculations involving photon de-tectors. The spectral photon sterance isabout 2.5 times greater at 1.6 μm than at0.51 μm for curve 4 data in Figure 1 of the article, which was generated by datataken at 89 percent moon illumination.But, again, what is important here is thespectral photon sterance integrated overwavelength in the appropriate passband,weighted by detector spectral response in photon units.

With an 89 percent moon, InGaAs andVisGaAs detectors will have about fivetimes the usable signal that the human eyehas available. Under those same condi-

14

l

www.masterbond.com

main@masterbond.com

at you

here’slooking

kidUSP Class VI Certified EpoxyAdhesive/Sealant EP30Med

High strength, rigid bonds Superb chemical resistance Optical clarity Low viscosity Easy application

Photonics Spectra July 2012

LETTERS

712Letters_Layout 1 6/25/12 3:44 PM Page 14

tions, a typical monochrome silicon sensorwill have about the same usable signal asan InGaAs camera. That should have beenexplained in more depth. Another advan-tage of airglow is that it comes from alldirections and reduces shadows in thescene, making it harder for an observer to miss a person or other item of interest.Moonlight casts shadows that get verylong at a low elevation angle, which in-creases scene clutter and tends to reducethe ability to find items of interest in ascene. Of course, if there is enough cloudcover, both moonlight and airglow can bereduced in intensity to the point where theonly viable imaging method is thermal.

Below is a plot of the data from curve 1in photon units, with a linear scale on boththe X- and Y-axes. The bands for the threetypes of sensors extend out to their respec-tive 50 percent points. A graph like thiswould have better served to illustrate thehuge advantage that an InGaAs or visible-enhanced InGaAs sensor has over both the unaided eye and low-light silicon sen-sors in no-moon conditions because theareas under the curves in each band are a

measure of the total available signal forthese three types of sensors (assumingsquare-band response and the appropriate50 percent cut points). The original Vatsiagraph is hard to interpret in this way be-cause of the semilog axis and the powerunits of measure. My graph also illustratesthat an extended InGaAs sensor that re-sponds to radiation out to 1.9 μm wouldmake use of SWIR airglow that conven-tional InGaAs won’t detect.

Dr. Austin RichardsFlir, Commercial Systems

Author responseWe would like to thank Dr. Richards forthe detailed comments on our article. Ingeneral, his letter is a good complementand clarifies our text with more in-depthinformation. It never was our intention to fully elaborate on the different topicsDr. Richards mentions in his letter. Withour introductory article, we intended togive a broad audience an idea of what canbe achieved in the wavelength band out-side of the visible region in the field ofnight imaging. This explains why most

of the text gives qualitative arguments tocome to the (correct) conclusion, and notso much a quantitative reasoning thatwould not be compatible with the limitedlength or scope of the article.

We believed that as Photonics Spectrais not peer-reviewed, it was not immedi-ately the proper medium in which to pub-lish a complete, in-depth analysis of night-glow and low-light-level imaging, but itwas perfect to show the possibilities andpotential of the InGaAs-based detectorsystems Xenics currently produces. It isworth mentioning that we have receivedseveral other positive comments on thisarticle from readers, who found it a nice,refreshing introduction to the topic.

We agree with Dr. Richards that itwould be interesting to write a more de-tailed article on the subject, one thatwould allow the interested reader to be-come more acquainted with the underly-ing physical mechanisms on different system levels.

Jan Vermeiren, Xenics NVLouvain, Belgium

l

Optics for Avionics

Unique Coatings

Fast Turnaround ofCustom Products

Precision Optical Components

Commercial Components

Glass Substrates

Complete Fabrication Capabilities

Advanced Thin Film Coatings

Aerospace / Defense / Military

Laser Manufacturing

Photovoltaics

Optics. Coatings. Precision.

3600 West Moore Avenue, Santa Ana, CA 92704 / 714.540.0126 / info@pgo.com

PG&O. Where optical elements take flight.

www.pgo.com

LETTERS

712Letters_Layout 1 6/25/12 3:44 PM Page 15

What’s Online

Photonics Spectra July 2012

Photonics Media’s industry-leading site features the latest industry news and events from around the world.

The Light Matters video player nowfeatures tabs that will take you directly to each story in the show.And, within the show itself there are now clickable links to read eachone of our related stories on Photonics.com. Just look for the “Read theStory” link in the upper left corner ofthe player. For the latest edition, visit: Photonics.com/LightMatters.

2013 Prism Awards – Call for Entries!The Prism Awards for Photonics Innovation, a joint collaborationbetween Photonics Media and SPIE, is a leading internationalcompetition celebrating innovation and honoring new product invention.

Applications are being accepted until Sept. 14, 2012. Enter to win – see if your product measures up!

Join Us for a Free Webinar2012 Webinar Series - Expert Briefings

Advances in Biomedical PhotonicsThursday, July 19, 2012 - 1 p.m. EDT/ 10 a.m. PDT/ 5 p.m. GMT/UTC

Photonics Media will host:

Lihong V. Wang, PhD, Gene K. Beare DistinguishedProfessor, Optical Imaging Laboratory, Department of Biomedical Engineering, Washington University, St. Louis. Wang will speak on “Photoacoustic Tomography: Ultrasonically Breaking Through the Optical Diffusion Limit.”

Meng Cui, PhD, Lab Head at Howard Hughes Medical Institute, Janelia Farm Research Campus. Cui will present “Iterative Multiphoton Adaptive Compensation Technique for Deep Tissue Microscopy.”

To register, visit: Photonics.com/Webinars

712Online_AugPS_Layout 1 6/25/12 4:34 PM Page 16

OPTICS

COATINGS

ASSEMBLIES

HENE LASERS

303.938.1960 | reoinc.comResearch Electro-Optics, Inc. Boulder, Coloradoprecision optical solutions

™ Covering the full spectrum of your photonics needs

Think REO

the tools to deliverOptical Coatings

712_ResElectroOptics_toolbox_Pg17_Layout 1 6/25/12 4:04 PM Page 17

18 Photonics Spectra July 2012

In the August issue of

Photonics Spectra …

Check out a sample of the new digitalversion of Photonics Spectra magazine at www.photonics.com/DigitalSample. It’s a whole new world of information forpeople in the global photonics industry.

Photonics HotspotsA list of the most important spots forphotonics work – both research andmanufacturing – around the globe.

Photonics Honor RollA list of the biggest and brightest photonics stars on the academic front.

Mergers & AcquisitionsA list of the companies that havemerged or that acquired other companies from July 2011 to June 2012.

Future Game-ChangersThe people whose work will likelychange the photonics world – and our lives.

Reader Participation Poll Results

The August issue of Photonics Spectra is our annual List Issue. Content will include:

Other featured content will include:

Where the Jobs AreA longtime recruiter in the photonics industry looks at recent moves, the most popular job prospects, and what new grads, the newly laid-off and other special groups can do to make themselves more attractive to prospective employers.

Invisibility – When and How?From Star Trek to James Bond and on again to the Halo video game series, invisibility cloaks have long captured our imagination. We explore some of the latest advances in optical cloaking technology and the many potential applications.

You'll also find all the news that affectsyour industry, from tech trends and market reports to the latest products and media.

712Online_AugPS_Layout 1 6/25/12 4:34 PM Page 18

NOW YOU HAVE A CHOICE.

www.edmundoptics.com/cage-system

USA: +1-856-547-3488EUROPE: +44 (0) 1904 788600

ASIA: +65 6273 6644JAPAN: +81-3-5800-4751

TRY OURCAGE SYSTEM!Ideal for Prototyping and University Research

Flexible and Modular Structure

Diverse Component Offering

N EW

WE DESIGN. WE MANUFACTURE. WE DELIVER.

more optics | more technology | more service

Booth 1116

START BUILDING NOW!Contact our Tech Support

Team to get Started

712_Edmund_Cage_Pg19_Layout 1 6/25/12 4:05 PM Page 19

Single nanomaterial yields a laser rainbowPROVIDENCE, R.I. – Nanocrystals thatproduce red, green and blue laser lightfrom a single material could lead to digitaldisplays and other devices that employ avariety of laser colors simultaneously.

Red, green and blue lasers have becomesmall and cheap enough to be integratedinto products ranging from Blu-Ray DVDplayers to fancy pens, but each color ismade with different semiconductor materi-als and by an elaborate crystal growthprocess.

Now, a prototype technology developedat Brown University and at QD Vision ofLexington, Mass., can achieve all threecolors using materials consisting of col-loidal quantum dots. The colloidal quan-tum dots have an inner core of cadmiumand selenium alloy and are coated withzinc, cadmium and sulfur alloy and propri-etary organic molecular glue.

The method was described onlinein Nature Nanotechnology (doi: 10.1038/nnano.2012.61).

“We are actively working with cadmium-free colloidal quantum dots such as in-dium phosphide,” Brown senior researchassistant Cuong H. Dang told PhotonicsSpectra. “Benefits are obvious with non-toxic materials.”

To create a laser display with arbitrarycolors such as shades of pink or teal, threeseparate material systems would need tocome together in the form of three distinctlasers that would not have anything incommon, according to Arto Nurmikko,professor of engineering at Brown. Instead,a new class of materials called semicon-ductor quantum dots was introduced.

QD Vision chemists synthesized thenanocrystals using a wet chemistry pro-cess that enables precise variation of sizeby altering production time. To producedifferent laser light colors, the only vari-able that must change is size: 4.2-nm cores produce red light, 3.2-nmones emit green light, and 2.5-nm onesshine blue. Other sizes would produceother colors along the spectrum.

“I don’t see any problem to produce allvisible colors with our technology,” Dangsaid. “But I did receive a request for theinfrared range: 1- to 2-μm wavelength,

which we have not yet achieved.”The coated pyramids, with improved

quantum mechanical and electrical per-formance, require 10 times less pulsed energy, or 1000 times less power, to pro-duce laser light than previous attempts.

A batch of colloidal quantum dots pre-pared to the Brown-designed specifica-tions yields a vial of viscous liquid thatsomewhat resembles nail polish. This liquid is used to coat a square of glass or a variety of other shapes to make a laser.When the liquid evaporates, severaldensely packed solid, highly ordered lay-ers of nanocrystals remain on the glass.By sandwiching this glass between twospecially prepared mirrors, the researcherscreated a vertical-cavity surface-emittinglaser (VCSEL) – the first working VCSELwith colloidal quantum dots.

The alloy in the nanocrystal’s outercoating reduces an excited electronic staterequirement for lasing and protects thenanocrystal from a kind of crosstalk thatmakes it hard to produce laser light, Nur-mikko said. Besides reducing crosstalk,the nanocrystal’s structure and outercladding reduce the amount of energy

needed to pump the quantum dot laser.The new approach’s structure enables thedots to act more quickly, releasing lightbefore heat is lost as a result of a phenom-enon known as the Auger process.

“The alloy for shell zinc cadmium sul-fide was rooted from our experience withII-VI semiconductor materials in bulk andthin-film forms a while ago,” Dang said.“There are a number of ligands involvedin optimizing the process. We tried botharomatic and aliphatic ligands.”

Next, the scientists hope to tackle theirsystem’s heating problem and to enableelectrical injection as opposed to the cur-rent optical injection to provide final prod-ucts, Dang said.

“We have managed to show that it’s possible to create not only light, but laserlight,” Nurmikko said in a university re-lease. “In principle, we now have some benefits: using the same chemistry for allcolors, producing lasers in a very inexpen-sive way, relatively speaking, and the abil-ity to apply them to all kinds of surfaces,regardless of shape. This makes possibleall kinds of device configurations for thefuture.”

NEWSTECH

Photonics Spectra July 201220

A closer look at the most significant photonics research and technology headlines of the month

Colloidal quantum dots – nanocrystals – can produce lasers of many colors. Cuong Dang manipulates a green beam that pumps the nanocrystals with energy, in this case producing red laser light (at left). Courtesy of Mike Cohea/Brown University.

712TechNews_Layout 1 6/25/12 3:56 PM Page 20

Coupled lasers cancel each other outVIENNA – The discovery that couplingtwo microlasers shuts them both off in-stead of emitting more light could provesignificant for technologies that combineelectronics and photonics.

The “laser blackout” effect, discoveredby scientists at the Vienna University ofTechnology (TU Vienna), working withcolleagues at Princeton and Yale universi-ties in the US and at ETH Zurich, usesnew methods developed at TU Vienna tosolve the complicated equations that de-scribe the problem.

“We were interested in what happenswhen each of the lasers in the coupled pairis pumped independently of the otherone,” Matthias Liertzer of TU Vienna saidin an interview with Photonics Spectra.“Although such setups have already beenrealized experimentally, we are not awareof any thorough theoretical investigationthat has [been] performed with regard topumping the disks individually.

“It was during these investigations thatwe noticed the effect of the laser turningoff, although the overall pump strength inthe system is increased. Since this behav-ior is quite counterintuitive, we firstchecked whether there was no mistake inour calculations, but soon realized that theobserved effect can be linked to the occur-rence of an ‘exceptional point’ in the un-derlying lasing equations.”

Exceptional points occur when two res-onator modes trapping light for a compar-atively long time amplify enough to bebrought above threshold and begin to lase.

“Researchers have studied exceptionalpoints in lasers before; however, theyneeded to change the shape of the laser inorder to observe the influence of such apoint,” Liertzer said. “This is experimen-tally cumbersome and can only be per-formed using mechanically deformablelaser cavities. We go beyond this limita-tion by demonstrating that the effects ofan exceptional point can be seen by a suit-able variation of the applied pump.”

The team discovered that when onelaser is shining and the laser next to it isturned on gradually, complex interactionsbetween the two can lead to a total shut-down of light emission. Surprisingly,

pumping the second laser does not neces-sarily increase the brightness of the cou-pled system, and supplying more energycan reduce the brightness until both lasersbecome dark.

The interplay between the lasers is morecomplicated than lightwaves interferingwith one another and canceling each otherout, the researchers say.

“This effect is not just about wave inter-ference,” Liertzer said. “It is a combina-tion of interference and light amplifica-tion, which can lead to seeminglyparadoxical effects.”

Next, the scientists will collaborate withcolleagues from the Photonics Institute atTU Vienna on an experimental realizationof the effect. After that, they plan to inves-tigate whether exceptional points can be

found in more intricate structures such asrandom lasers, Liertzer said.

He believes that their paper, which was published in Physical Review Letters(doi: 10.1103/PhysRevLett.108.173901),will bring together two active communi-ties.

“On the one hand, there is the commu-nity of non-Hermitian physics, where ex-ceptional points, gain/loss structures,etcetera, are at the center of attention,” hesaid. “On the other hand, there is the verylarge laser community with over 50 yearsof experience and a vast number of appli-cations where lasers are employed. Withour paper, we bridge these two communi-ties by showing how the interesting non-Hermitian physics of exceptional pointscarries over to lasers.”

21Photonics Spectra July 2012

Two coupled microlasers with light beams. Courtesy of TU Vienna.

Solar cell-like implant stimulates optic nerveSTANFORD, Calif. – A new retinal pros-thesis that uses technology similar to thatfound in solar cells could restore sight tothose who suffer from degenerative eyediseases such as macular degeneration andretinitis pigmentosa.

Researchers at Stanford UniversitySchool of Medicine have developed gog-gles that interface with a tiny chip in theretina and convert light into electrical sig-nals, stimulating the optic nerve and al-lowing patients to see once more.

“While high-fidelity color vision is along way off, some patients with retinalprostheses have so far been able to readlarge fonts (with visual acuities on theorder of 20/1000) and complete daily tasksin ways that they could not before treat-ment,” postdoctoral scholar Dr. James

Loudin told Photonics Spectra. The re-search team hopes to achieve visual acuitybetter than 20/200 and is focusing its ef-forts on assessing the visual acuity andcontrast sensitivity in vivo, said Dr. DanielPalanker, an associate professor of oph-thalmology at Stanford.

The goggles work similarly to solarpanels on the roof of a building, convert-ing light into electric current. Instead ofthe current flowing to household appli-ances, however, it would flow into retinas,Palanker said.

The devices are equipped with a cameraand a pocket computer that feed images to a liquid crystal display, which is thenbeamed to the implant using near-infraredlaser pulses. The light is received by aphotodetector silicon chip, which converts

712TechNews_Layout 1 6/25/12 3:56 PM Page 21

it into an electrical current. The currentstimulates the optic nerve, sending theimage data to the brain’s vision centers.The whole process is similar to how a dig-ital camera takes a picture.

The chip is the size of a pencil pointand contains hundreds of light-sensitivediodes. Using light to transmit the data instead of wire, coils or antennae such asother current implants keeps the chip from

becoming bulky and makes it easier forimplantation.

Several other retinal prostheses are inthe works, and at least two are in clinicaltrials. Second Sight of Los Angeles devel-oped a device that was approved in Aprilfor use in Europe, and German prosthesismaker Retina Implant AG recently an-nounced the results from its clinical test-ing in Europe.

“Second Sight uses RF telemetry topower and transmit data to an array of 60electrodes over several square millimetersin their Argus II device,” Loudin said. “Wehave proven the functionality of single pix-els as small as 70 μm, with pixel densitiesof up to 178 pixels per square millimeter.The Retinal Implant AG device has simi-larly high resolution but requires additionalimplanted hardware to power it.”

The advantages of Stanford’s approach,Loudin said, are “its high pixel density,easy scalability and lack of separate, bulkypower-receiving hardware, which makessurgical implantation easier and thus re-duces the risk of complications.”

The researchers tested the effectivenessof the implants in the retinas of both blindand normal rats. The retinal ganglion cellsof treated normal rats were responsive tostimulation by plain visible light as well asto the near-infrared, which showed that theimplants were responsive to nonvisiblelight. In the blind rats, the scientists ob-served that visible wavelengths generatedvery little ganglion response, whereas thenear-infrared caused spikes in the rats’neural activity similar to those in normalrats. The blind rats, however, needed sig-nificantly more infrared light to achievethe same activity levels as in normal rats.

Although these technologies inducecolor perception in patients, this percep-tion is difficult to predict and control,Loudin said. These electrically stimulatedpercepts enable patients to see a variety of

22

t TECHNEWS

Photonics Spectra July 2012

This pinpoint-size photovoltaic chip (upper right corner) is implanted under the retina in a blind rat to restoresight. The center image shows how the chip comprises an array of photodiodes, which can be activated bypulsed near-infrared light to stimulate neural signals in the eye that propagate to the brain. A higher-magnifi-cation view (lower left corner) shows a single pixel of the implant, which has three diodes around the perimeterand an electrode in the center. The diodes turn light into an electric current, which flows from the chip into theinner layer of retinal cells. Courtesy of Daniel Palanker.

712TechNews_Layout 1 6/25/12 3:56 PM Page 22

colors, including yellow, blue, red and white.“A device with precise, predictable spatial control of the color

of these percepts across many patients is many years off.”The scientists next will evaluate the in vivo perceptual resolu-

tion of these devices, and are working to understand how high a resolution is possible with this approach. They are seeking asponsor to support human clinical trials, which they say will depend on the availability of industrial partners and funding.

The research was published online in Nature Photonics (doi:10.1038/nphoton.2012.104).

Laser creates cheaper free-form opticsAACHEN, Germany – A new process for fabricating smallbatches of nonspherical glass optical components will allow man-ufacturers to produce high-quality, customizable optical compo-nents of any geometry quickly and inexpensively.

Researchers at Fraunhofer Institute for Laser Technology useda computer-controlled CO2 laser to heat a square-shaped piece of fused silicon to its evaporation temperature (2230 °C), carvingaway at the silicon much as a sculptor would cut away sections of marble to create a statue.

The laser uses custom inputs to control how much silicon it removes and what shape it makes so that virtually any surfaceform can be produced. Once the silicon is shaped, it is reheated to near the evaporation point to reduce roughness; the materialstays polished while it cools. Further imperfections can be buffedout afterward using the same ablative process.

As the laser process is controlled by computer data, the inputscan easily be changed to create optical components to order. Thenew process also is estimated to speed up manufacturing time bya factor of 10, which coulddrastically increase pro-duction and drive downthe cost of manufacturing.However, before it can beapplied in industry, thetechnique must be opti-mized by increasing theprecision of the laser abla-tion and the quality of thepolishing process.

The researchers pre-sented their process atAKL, the InternationalLaser Technology Con-gress, on the Fraunhofercampus.

tTECHNEWS

Photonics Spectra July 2012

High-speed laser ablation of fused silica. Thelaser controls how much silicon it removes and what shape it makes to produce virtually any surface form. Images ©Fraunhofer Institute for Laser Technology ILT, Aachen.

The components take various forms after individual steps of the laser-based fabrication process.

712TechNews_Layout 1 6/25/12 3:56 PM Page 23

ATLANTA – A new technique can pro-duce single photons with specific proper-ties more efficiently and about 1000 times

faster than the current methods, an impor-tant advance for several research areas, including quantum information processing

and quantum network development. Alex Kuzmich, a professor at the Geor-

gia Institute of Technology, and his gradu-ate research assistant Yaroslav Dudin dis-covered that they could create a Rydbergatom (a highly excited atom that is verynear its ionization point) by shining laserson a dense cloud of rubidium-87 atomsthat were laser-cooled and confined to anoptical lattice.

The lasers excite one of the rubidiumatoms to the Rydberg state. Because of aninteresting electromagnetic property ofthese atoms, exciting one prevents othersin a 10- to 20-μm radius from transition-ing, an effect called the Rydberg blockade.This ensures that, on average, only onephoton will be emitted.

“The excited Rydberg atom needs spacearound it and doesn’t allow any other Ryd-berg atoms to come nearby,” Dudin said.“Our ensemble has a limited volume, sowe couldn’t fit more than one of theseatoms into the space available.”

Once they have an excited Rydberg

24

t TECHNEWS

Photonics Spectra July 2012

Single entangled photon creation unlocked

Georgia Tech graduate student Yaroslav Dudin and professor Alex Kuzmich adjust optics as part of researchinto the production of single photons for use in optical quantum information processing and the study of certain physical systems. Courtesy of John Toon.

712TechNews_Layout 1 6/25/12 3:57 PM Page 24

The latest research on optical engineering and applications, solar energy, nanotechnology, and organic photonics

Location San Diego Convention CenterSan Diego, California, USA

spie.org/aboutop

Conference dates 12–16 August 2012

Exhibition dates 14–16 August 2012

Conferences- Nanoscience + Engineering- Solar Energy + Technology- Organic Photonics + Electronics- Optical Engineering + Applications

2012

Register Today

12–16 August 2012

712_SPIE_Opt&Pho_Pg25_Layout 1 6/25/12 4:08 PM Page 25

atom, the researchers use a laser field to convert the energy of theatom into a quantum light field containing one photon.

The researchers hope to move on to building quantum logicgates between light fields, a great step forward for quantum com-puting and networking.

“If this can be realized, such quantum gates would allow us todeterministically create complex entangled states of atoms andlight, which would add valuable capabilities to the fields of quan-tum networks and computing,” Kuzmich said. “Our work pointsin this direction.”

The research is also promising for many other areas of physics. “Our results also hold promise for studies of dynamics and dis-

order in many-body systems with tunable interactions,” Kuzmichsaid. “In particular, translational symmetry breaking, phase transi-tions and nonequilibrium many-body physics could be investi-gated in the future using strongly coupled Rydberg excitations of an atomic gas.”

Kuzmich is also doing research on long-lived quantum memo-ries as part of a US Air Force Office of Scientific Research Multi-disciplinary University Research Initiative headed by GeorgiaTech.

The research, reported in Science Express (doi: 10.1126/science.1217901), was supported by the National Science Founda-tion and the Air Force Office of Scientific Research.

Release process holds promise for GaN semiconductorsTOKYO – Nitride semiconductors grow only on certain surfaces,and their utility is limited by the substrate on which they are fab-ricated. But a new release process not only makes the methodcheaper and easier, it also expands the potential uses of the mate-rials.

Yasuyuki Kobayashi and colleagues at Nippon Telegraph andTelephone Corp. (NTT) demonstrated the process with a tech-nique called mechanical transfer using a release layer (MeTRe).They grew a very thin hexagonal layer of boron nitride (h-BN)between a sapphire substrate and a gallium nitride (GaN)-basedsemiconductor. Sandwiched in the middle, the h-BN works as arelease layer, allowing the investigators to easily detach the semi-conductor and transfer it to other substrates without using expen-sive laser beam machining or chemical treatment.

GaN-based semiconductors have a wide range of applicationsin high-power electronic devices and light sources, but their util-ity is hampered by the thickness of the substrates on which theyare grown. The substrates are hard to separate from the GaN andcan be 100 times the size of the film. They also must be stable athigh temperatures because the GaN-based film’s growth tempera-ture is 1000 °C. Using the MeTRe fabrication process, GaN-based thin-film devices can be separated easily from their sub-strate and transferred onto other devices, and they can be grownon nearly any single crystal substrate. Both of these qualitiesgreatly increase their utility.

Boron nitride also is difficult to grow on a single-crystal sap-phire substrate because of a very different crystal structure. How-ever, the researchers optimized its growth using metallorganicchemical vapor deposition, which uses the constituent gases toencourage single-crystal, thin-film growth on the substrate’s surface. They also found that the GaN layers could be grown

t TECHNEWS

Photonics Spectra July 2012

712TechNews_Layout 1 6/25/12 3:57 PM Page 26

on top of the BN film if a buffer layer ofAl1�xGaxN, an aluminum/gallium nitridealloy, was used.

The MeTRe method of semiconductorfabrication is cheaper, faster and easierthan conventional methods; a worldwidemovement has been under way to developsuch an efficient technique. The processalso allows thin, flexible semiconductorswith a large surface area (up to 2 cm) tobe made. One key application of such asemiconductor is in the development of

flexible solar panels that are sensitive toUV wavelengths only and that can be putin windows to filter out the harmful rayswhile also collecting and storing solar energy. This can be accomplished easilyby attaching GaN-based solar cells to pre-existing silicon-based ones.

Other potential applications include thinLEDs, highly functional hybrid CMOSand flexible devices.

The research appeared in Nature (doi:10.1038/nature10970).

27

FormerlyPacific Silicon Sensor Inc.

Now

First Sensor, Inc.U.S.A. based subsidiary of

First Sensor AG, providing in-house design, manufacturing and testing of Si PIN, APD, PSD’s and

InGaAs Photodiodes

Standard, Custom, Hybrid and Integrated Solutions

First Sensor, Inc.5700 Corsa Avenue #105

Westlake Village, CA 91362 USAT 818 706-3400 F 818 889-7053

contact.us@first-sensor.comwww.first-sensor.com

Standard products available through www.mouser.com

Westlake Village, California

a tti company

®

MOUSERE L E C T R O N I C S

niaoralifC, illageestlake VW

ormerlFF

manufacpr

U

First Sensor

esting and tingturmanufacn, in-house desigviding opr

, Gensor Airst SFy of .S.A. based subsidiarU

, Inc.First SensorowN

.ensor Incilicon Sacific SPyormerllyFFo

esting n,

y of

, Inc.

and ItandarS

of Si PIN, APD

olutionsed Staregtnand Iid ybrom, Hust, Cdtandar

odiodeshots PaAnGIs and’’s, PSDof Si PIN, APD

ing

olutionsid

s and esting

A 91362 USA, CillageVestlake Wenue #105vorsa A5700 C

.nc, Iensorr,irst SF

tandarS

c

om.c.mouserr.wwwough ailable thrvts aoducd prtandar

om.c-sensor.firstwwwom.c-sensor.us@firstttaconc

F 818 889-7053T 818 706-3400

®

a tti company

E L E C T R O N I C SMOUSER

om

om

tTECHNEWS

Photonics Spectra July 2012

Comparison of the traditional methods of fabricating GaN semiconductors and the technique devised by Ya-suyuki Kobayashi and colleagues. Courtesy of NTT Science and Core Technology Laboratory Group.

Students’ QDs win regional Cleantech ChallengeSALT LAKE CITY – Students at the Uni-versity of Utah recently won $100,000 andfirst place in the regional CU CleantechNew Venture Challenge for their quantumdot technology.

Compared with other materials, quan-tum dots require less energy for emittinglight. The color of light emitted dependson the dot’s size. Large quantum dots produce light toward the red side of thespectrum, while smaller dots produce lighttoward the blue side. These man-madesemiconductor nanocrystals hold potentialfor a growing number of applications, including televisions, solar panels and cellphones.

Although the future of quantum dotslooks bright, the manufacturing processremains one of the biggest challenges foradvancing them. Conventional processesare expensive, require high temperatures

and produce low yields. Currently, a gramof quantum dots costs $2500 to $10,000.

Now, researchers at the University ofUtah may have a solution to such highmanufacturing costs. Their company, Navillum Nanotechnologies, is gaining national attention with the help of MBAstudents Ryan Tucker, Chris Lewis andAmeya Chaudhari, whose process useslower temperatures and produces lesswaste than the traditional method. The students focused on applications related to solar technology and energy efficiencyto win the regional title. They will use theprize money to refine their manufacturingprocess and increase its scale.

“The win reflects on the organizationswe have at the University of Utah to sup-port entrepreneurship,” Tucker said. “Italso helps me get excited that, even as students, we can do great things.”

712TechNews_Layout 1 6/25/12 3:57 PM Page 27

The students started the project throughthe Pierre and Claudette Lassonde NewVenture Development Center, which ispart of the David Eccles School of Busi-ness. The Lassonde Center links faculty

inventors with graduate students whowrite business plans for them. The univer-sity’s Energy Commercialization Centeralso helped mentor the team.

Navillum Nanotechnologies competedin the challenge against teams from ninestates. Other finalists were from the uni-versities of Colorado at Boulder and Den-ver, and from Maharishi University ofManagement in Fairfield, Iowa. The Utahteam won for its superior technology andbusiness plan, said Steve Herschleb, anMBA student in Boulder and programmanager of the competition.

“It was the attractiveness of the technol-

ogy and the growth potential,” Herschlebsaid. “There’s a little bit of risk; the mar-ket hasn’t fully embraced the technology.But the applications, from a scientificbasis, are very promising, and the marketis expected to be enormous in the future.”

Navillum also has received $155,000 in grants from the University of Utah, theUtah Governor’s Office of Economic Development and the Utah Science Tech-nology and Research initiative.

The student team will advance to thenational championship, to be held in Junein Washington, D.C. The competitions arefinanced by the US Department of Energy.

28

t

Schneider Compact C-Mount lenses lockin calibrated settings, so focus and boresightstay true no matter now harsh the conditions.Offering virtually indestructible constructionand visible through near IR performance.

As small and robust as������������ can be.

Schneider KreuznachCompact C-Mount Lenses

In the USA: +1 631 761-5000Outside the USA: +49.671.601.205

www.schneiderindustrialoptics.com

TECHNEWS

Photonics Spectra July 2012

MBA students from the David Eccles School of Business at the University of Utah pose with the$100,000 check they won at the CU Cleantech New Venture Challenge for a quantum dot manu-facturing process that uses lower temperatures andproduces less waste than previous methods. Fromleft, Ameya Chaudhari, Chris Lewis and RyanTucker. Courtesy of University of Utah.

Four-wave mixing generates superluminal pulsesGAITHERSBURG, Md. – A novel four-wave mixing technique that restructuresparts of light pulses to travel faster thanthe speed of light could improve the tim-ing of communications signals and helpexamine the propagation of quantum correlations.

Einstein’s theory of relativity states that

light passing within a vacuum representsthe universal speed of light. A short burstof light emerges as a type of symmetriccurve. The curve’s leading edge cannotsurpass the speed of light, but the peak of the pulse can be altered forward andbackward.

Recent experiments demonstrated that,

712TechNews_Layout 1 6/25/12 3:57 PM Page 28

by increasing the leading edge of the pulseand cutting the back end, “uninformed”faster-than-light pulses with increasednoise are generated. However, four-wavemixing produces less noisy, cleaner andmore rapid pulses by rearranging orrephasing the pulse-generating lightwaves.

In the four-wave mixing technique developed by scientists at the National Institute of Standards and Technology,laser light “seed” pulses up to 200 ns longare introduced into a heated cell contain-ing atomic rubidium vapor and a separate“pump” beam at a different frequencyfrom the seed pulses. The seed pulse isamplified by the vapor, shifting its peakforward so that it becomes superluminal.The photons from the inserted beam inter-act with the vapor to generate a secondpulse, called the “conjugate” because ofits mathematical relationship to the seed.The speed of the peak is based on the conditions inside the laser and on how it is tuned.

The experiment yielded pulse peaks thatarrived 50 ns faster than light travelingthrough a vacuum.

The team now is looking to use themethod to study quantum discord, whichmathematically defines the quantum infor-mation between two correlated systems

such as the conjugate and seed pulses. Theresearchers hope to determine how usefulthis light could be to transmit and processquantum information.

t

HANDS-FREE MONOLITHIC OEM

LIGHT ENGINE

www.cvimellesgriot.com

CYTOMETRY MICROSCOPY FLUORESCENCE IMAGING

cvimellesgriot.com/Monolithic

lasers@cvimellesgriot.com

1 760 438 2131

Pointing Stability < 5 μrads/°C

Power Stability < 2% peak-peak

Amplitude Noise Stability < 2% peak-to-peak

Rugged Package

Stable to <25 g at 11 msec

Operating Temperature: 10-40 °C

SEQUENCING

A light engine you can ship, shake, and shock and not

have to realign. Worry free and truly hands-free. Select

3 or more output wavelengths from 405 to 640 nm and

powers up to 90+ mW.

TECHNEWS

In four-wave mixing, researchers send “seed” pulses of laser light into a heated cell containing atomic rubidiumvapor along with a separate “pump” beam at a different frequency. The vapor amplifies the seed pulse andshifts its peak forward, making it superluminal. At the same time, photons from the inserted beams interact withthe vapor to generate a second pulse, called the “conjugate.” Its peak, too, can travel faster or slower, depend-ing on how the laser is tuned and on the conditions inside the gain medium. The chamber contains rubidium-85 gas at ~116 °C. Courtesy of NIST.

712TechNews_Layout 1 6/25/12 3:57 PM Page 29

30

t TECHNEWS

Photonics Spectra July 2012

narrow and parallel beam. Farther alongthe instrument, a silicon prism was placedat a height where it refracted half of thegamma ray beam. The refraction of thishalf-beam was then detected by a secondsilicon crystal and compared with the half consisting of unrefracted gamma rays.

They discovered that the energy of the

gamma rays increased the falling refrac-tion values, then suddenly increased tolarger positive refraction values, similar to those of visible light. These were muchhigher values than anyone expected.

The researchers now believe that by replacing the silicon prisms with higher-refracting materials such as gold, they can increase refraction to a level where it

Gamma ray refraction could launch nuclear photonicsGRENOBLE, France – An experiment inwhich gamma rays were bent like ordinarylight overturns decades of theoretical pre-dictions and opens the door to a new fieldof research called nuclear photonics.

Gamma rays are essentially a highly en-ergetic form of light. Able to penetrate al-most any material, they now can bend andfocus, which could lead to powerful newmedical applications, including imagingtechniques and targeted cancer treatments.

Using a version of a common classroomexperiment with glass prisms, scientistsfrom Laue-Langevin Institute (ILL) andLudwig Maximilian University of Munichrefracted the rays at the highest energiesever recorded.

In the same way that light beams can be bent and split with glass prisms, the researchers used a silicon prism to bendgamma rays. They analyzed the gammarays produced using ILL’s PN-3 facilitythrough two silicon crystals, the first preselecting them as they came out of the reactor and directing them into a very

At the high-resolution gamma ray facility GAMS at ILL, gamma rays now can bend and focus; this couldlead to new medical applications such as targeted cancer treatments and novel imaging techniques. Image: ©ILL/Bernhard Lehn Fotodesign Studio@bernhardlehn.de.

712TechNews_Layout 1 6/25/12 3:58 PM Page 30

Coming July 19, 2012

Advances in Biomedical Photonics

2 0 1 2 W E B I N A R S E R I E S

Expert BriefingsIn-depth presentations and interactive Q&A featuring top industry experts.

For more information, visit:www.Photonics.com/Webinars

To become a sponsor, contact your sales representative at (413) 499-0514, or email advertising@photonics.com.

Hosted by Photonics MediaLihong V. Wang, PhD, Gene K. Beare Distinguished Professor, Optical Imaging Lab -oratory, Department of Biomedical Engineering,Washington University, St. Louis. Wang will speakon "Photoacoustic Tomog raphy: UltrasonicallyBreaking Through the Optical Diffusion Limit."

SEPTEMBER – Solar

NOVEMBER – Space

Meng Cui, PhD, Lab Head at Howard HughesMedical Institute, Janelia Farm ResearchCampus. Cui will present “Iterative MultiphotonAdaptive Compensation Technique for DeepTissue Microscopy.”

Sponsored by

712_WebinarAd_M&H_Pg31_Layout 1 6/25/12 5:03 PM Page 31

can realistically be manipulated for opticaltechniques.

“Twenty years ago, many peopledoubted you could do optics with x-rays –no one even considered that it might bepossible for gamma rays, too,” said Dr.Michael Jentschel, an ILL research scien-tist. “This is a remarkable and completelyunexpected discovery, with significant implications and practical applications.These include isotope-specific microscopywith benefits across the scientific disci-plines, through to direct medical treatmentand even tools to address major nationalsecurity issues.”

Potential applications include more selective, less destructive medical imagingtechniques achieved by enriching a partic-ular isotope in a cancer and monitoringwhere it goes, improved production andtrialing of new, more targeted radioiso-topes for cancer treatment, and remotecharacterization of nuclear materials or radioactive waste.

The work appeared in Physical ReviewLetters (doi: 10.1103/PhysRevLett.108.184802).

32

t

Cleanroom-Ready Motion Solutions...

Aerotech manufactures the widest variety of cleanroom compatiblemotion solutions for high performance applications such as waferinspection, metrology and lithography.

Aerotech Cleanroom-Ready Motion Systems Feature:• Low particulate generating cable management systems

• Cleanroom compatible, hydrocarbon-free lubricants

• Special material surface treatments

• Manufacturing processes that are specifically designed tomaximize system-level cleanliness.

Dedicated to the Science of MotionAerotech, Inc., 101 Zeta Drive, Pittsburgh, PA 15238Ph: 412-963-7470 • Fax: 412-963-7459 • Email: sales@aerotech.com

www.aerotech.comAH0510C_TM

A e r o t e c h W o r l d w i d eUnited States • France • Germany • United Kingdom • China • Japan • Taiwan

...Are Used in Sub-Class 10 Cleanrooms Around the World

TECHNEWS

Photonics Spectra July 2012

SAN DIEGO – For the first time, a her-alded single photon has been generatedfrom a silicon chip.

The discovery – made by a consortiumof researchers from the University of Cali-fornia, San Diego, the National Institute of Standards and Technology (NIST) andthe Polytechnic Institute of Milan in Italy– overcomes an important barrier to gener-ating single photons using a tiny, chip-scale device constructed from silicon. Itcould lead to applications in cryptography,radiometry, imaging and telemetry, andcould pave the way for new devices forquantum communication, ultralow-powercomputing and other technologies, nowthat all three basic components of a quan-tum transceiver – sources, controllable circuits and detectors – have been demon-strated using silicon photonics.

Heralded photons are the second in apair of spontaneously generated photons:When the first hits a detector and providestiming information, it “heralds” the com-panion photon, which is then in a quantum

mechanical single-photon state. The researchers fabricated the 0.5 �

0.5-mm device using CMOS-compatibleprocesses on 200-mm silicon-on-insulatorwafers at an external collaborative re-search foundry. The device operates atroom temperature and generates quantumlight in the near-1550-nm wavelengthrange.

“This is in the infrared range, and it istechnologically important because thosewavelengths are used in today’s opticalfiber networks,” said Shayan Mookherjea,an associate professor of electrical andcomputer engineering at UC San Diego’sJacobs School of Engineering. “Chip-scalesingle-photon sources could be used inquantum devices, networks and systems to bring about enormous improvementsover their classical counterparts, in termsof speed or security or computationalcomplexity.”

In a recent demonstration, silicon wave-guide circuits consisting of a network ofcontrollable couplers and interferometers

First heralded single photon generated from silicon

712TechNews_Layout 1 6/25/12 3:58 PM Page 32

33

tTECHNEWS

Photonics Spectra July 2012

showed quantum interference and entan-glement manipulation using off-chip lightsources, and on-chip single-photon coun-ters were formed using a superconductinglayer deposited as a cladding of a siliconnanophotonic waveguide.

“Silicon is not an efficient light emitter,so creating a single-photon source usingsilicon was challenging,” said Junrong

Ong, a graduate student at UC San Diego.“Our demonstration of an on-chip, single-photon source is a first step towardsachieving on a single silicon chip all thethree main components needed for fullyintegrated quantum photonics.”

“While a variety of single-photonsources have been developed, they ofteninvolve nonstandard fabrication processesor require cryogenic cooling,” said KartikSrinivasan of NIST. “The devices studiedby our team, in contrast, operate at roomtemperature and are built using maturefabrication techniques already applied inthe manufacturing of computer chips.”

To generate single photons, the scien-tists split pump photons into pairs at dif-ferent wavelengths resulting from the optical nonlinearity present in the device.They next demonstrated the process ofheralded single-photon generation using a novel silicon nanophotonic waveguideconsisting of a linear array of coupled microresonators.

“Our novel device not only providesplug-and-play resonant enhancement ofdesired processes, but it also suppresses

Dr. Shayan Mookherjea, associate professor in theMicro-/Nanophotonics Lab at UC San Diego. Courtesy of UC San Diego.

undesired processes by filtering out non-resonant pump noise effects,” Mookherjeasaid.

The devices used in the project weremeasured using telecommunications-bandsingle-photon counters developed by pro-fessor Alberto Tosi and collaborators atPolytechnic Institute. The scientists per-formed a photon correlation measurementin which the heralded light was split intotwo separate paths and detected using sin-gle-photon counters. They confirmed that,when working with single photons, itshould not be possible to see heraldedphotons on both detectors simultaneously,known as “anti-bunching.”

The research was presented at CLEO:2012, the Conference on Lasers and Elec-tro-Optics, held in May in San Jose.

Ashley N. Paddockashley.paddock@photonics.com

712TechNews_Layout 1 6/25/12 3:58 PM Page 33

Software gives photonics designers more powerGHENT, Belgium – A new open sourcesoftware platform will offer greater powerand flexibility to designers of photoniccomponents and complex photonic inte-grated circuits.

IPKISS, developed by Ghent Universityand nanoelectronics research center Imecof Louvain, is a generic and modular soft-ware framework for the parametric designof photonic integrated components andcircuits. It allows designers to quickly define photonic components, directly sim-ulate them in electromagnetic solvers andintegrate them into a circuit on a photo-mask for fabrication. The platform also in-tegrates with third-party simulators andcan be customized for other domains re-lated to micro- and nanoelectronics, suchas microfluidics, plasmonics and micro-electromechanical systems.

Internally, the component knows how to generate its layout, its input and outputconnections with other components, its internal circuit representations and so on.This ensures a separation between the formal specification of a component orcircuit and different representations thatcan be derived.

Components can be defined to acceptoutside technology information providedby the fab, effectively allowing a designthat could be fabricated in various loca-tions. Design kits for Imec’s silicon pho-tonics technologies are available throughePIXfab, a European foundry service forsilicon photonics prototyping, and throughImec directly.

The IPKISS design approach results ina productive design cycle with little mar-gin for copy-and-paste errors, the develop-ers say. This contrasts with a design workflow that is static and cannot be influencedby the user, or where the user is limited tothe functionality provided in a graphicaluser interface.

The software is available by means of afree GPLv2-licensed code base as well asthrough custom developer and commerciallicenses. It was conceived in 2002 by theuniversity’s Photonic Research Group andImec as a programmable generator ofmask layouts written in Python, but it hasevolved significantly since its introduc-tion. It was launched at SPIE PhotonicsEurope 2012 during the exhibitor productdemonstrations.

34 Photonics Spectra July 2012

TRACKFAST

The IPKISS frameworkis available under three

open source licenses:• For the community, a GPLv2-

licensed code base will allow access to the framework at nocharge. The objective of this license scheme is to encouragepeople to develop the IPKISSframework, so a thriving com-munity can evolve around it.

• For the developer, a custom license with an annual fee allowsthe licensee to develop plug-insand add-ons for distribution.

• For software developers who wishto incorporate IPKISS into a prod-uct and bundle a modified ver-sion of the code base with theirown additions, there is also acustom commercial license; this license and its cost will betailored to each individual case.

LME 2012 expands educational offeringsBY GEOFF GIORDANO

Editor’s note: This article was originallypublished in the May/June issue of LIAToday.

SCHAUMBURG, Ill. – LIA has unveiledan expanded educational track for LME2012, bringing more basic courses and a pair of two-hour tutorials addressingwelding and joining and ultrafast laserprocesses. The event will again offer attendees guidance on creating effective, efficient laser-based production systems to increase profitability in a broad range

of applications, predominantly aerospace,automotive and medical.

Three new courses addressing the fun-damentals of laser additive manufacturing,cutting and robotics have been addedalong with the two tutorials. These willappear alongside primer sessions on themain types of lasers used for manufactur-ing, creating laser systems and establish-ing the return on investment.

In addition, a new two-day Laser Weld-ing & Joining Workshop, chaired by LIApast president and Schawlow award win-ner Prof. Eckhard Beyer of FraunhoferIWS, will run concurrently with LME.“As many laser manufacturers and systembuilders are engaged in the workshop, thiswould be an ideal opportunity to get appli-cation-related questions answered and getnew ideas on how to use lasers,” Beyersaid. “We are going to unite many people

from the laser community who are shapingthe way the world of lasers is today. Thiswill make it possible to address lasersfrom the basics to high-end applications.”

The workshop will feature 18 presenta-tions, spread out over two days to allowample time for attendees to interact directly with OEMs in the exhibit hall.

“The workshop will start with shortcourses presented by industrial researchexperts to give a sound overview of laserbasics and current developments,” Beyersaid. “End users with long-standing expe-rience will present their solutions to thetypical challenges of laser applications.”

Some of those applications will includepower-train welding, remote welding, hy-brid welding and micro applications, henoted. Such applications are being refinedconstantly as lasers continue to evolve.

“We still see a big impact of the

LIA’s Lasers for ManufacturingEvent will return Oct. 23-24

to the Renaissance SchaumburgConvention Center Hotel.

712FastTrack_Layout 1 6/25/12 3:43 PM Page 34

712_SmithersApex_Pg35_Layout 1 6/25/12 4:10 PM Page 35

tremendous rise in beam quality and en-ergy efficiency,” Beyer said. “Here the application fields are expanded in manyways: ultralow distortions or the realiza-tion of new mixed-material joints like copper-aluminum using precisely shapedweld pools. Also, remote-beam applica-tions are now standard; that was a field restricted to expensive high-brightnesslasers just a few years ago.

“Furthermore, laser size reduction is akey development; many lasers are now so small that machine integration is muchsimpler and can be done in a way not pos-sible before.”

Focus on ultrafast lasersAlthough this year it is a tutorial, next

year the program on ultrafast lasers couldgrow into another two-day workshop, or-ganizers said. For the inaugural session,the educational track will feature technicalexamples, a survey of Technology Readi-ness Level (TRL) 1-9 materials and anoverview of markets and materials, saidLIA president Prof. Reinhart Poprawe ofFraunhofer ILT. He added that the sessionwill be geared toward those involved withoptical systems and scanning technologies,as well as toward users of precision ma-chining applications with accuracy in therange of 10 μm and below.

“The development of ultrafast laserswith pulse durations of some 100 fs to 10 ps on an industrial scale with powersup to the kilowatt class has led to a newlevel of laser processing with ultimate

36

f

Photonics Spectra July 2012

FASTTRACK

LME 2012 offers courses, tutorials, networking opportunities and more to give attendees guidance on creating laser-based production systems for a broad range of applications including aerospace, automotive and medical. Images courtesy of LIA.

The exhibition at LME 2012 will allow companies to connect with potential customers.

To learn more about LME, or to register for the event, visit www.laserevent.org.

712FastTrack_Layout 1 6/25/12 3:43 PM Page 36

processing quality,” Poprawe said. “Starting with physical basicson ultrashort pulse interaction phenomena, the tutorial will give asurvey on different applications from electronics, energy topicsand tooling technology to large area processing for tribology optimization and surface functionalization.”

The tutorial is particularly suited for engineers and scientistsfrom machine suppliers and end users, Poprawe said. Also, “Manufacturers of ultrafast lasers and optical systems (scanningtechnologies) will learn about the requirements on system technology with respect to laser parameters and processing parameters.”

“Ultrashort pulsed lasers are heading to the edge of mass in-dustrialization and will undergo similar growth rates like otherlasers in the past,” Poprawe added.

Applications for ultrafast lasers include the biomedical, auto-motive and tool and molding industries; LED and OLED light-guiding systems; photovoltaics and energy storage; and generalsurface processing. The tutorial will help shed some light on thecurrent debate over what kind of pulse lengths are optimal forwhat materials, how best to apply high-repetition lasers to work-pieces, and how researchers and manufacturers can concentrateon shortening manufacturing cycle times.

Safety educationIn addition to spotlighting the bottom-line benefits of lasers,

the working systems at the event will put the need for laser safetyfront and center.

LIA education director Gus Anibarro, also the event’s lasersafety officer, will give a one-hour presentation on assessingbeam and nonbeam hazards in the laser manufacturing environ-ment and how to ensure the safety of operating personnel.

Anibarro will condense his extensive laser safety experienceinto an information-packed session that highlights preventionrudiments addressed more fully in LIA’s two-, three- and five-daylaser safety courses. The crash course in proper laser use willcover the classes of lasers, direct vs. reflected exposure, the needto control laser-generated air contaminants, skin and eye hazards,and how to choose eyewear of the proper optical density.

Networking made easyHeld in proximity to a large number of manufacturers and job

shops, LME has something for everyone, from those seeking torefine current laser systems and applications to those assessingnew ways to employ lasers in production. While the educationalprogram provides tools to help assess the benefit of investing in lasers, the exhibit floor provides a real-time marketplace to discuss applications as well as primary and ancillary equipmentwith top-tier suppliers.

To that end, LME will again feature the Laser TechnologyShowcase, a stage at the front of the exhibit hall that will be used for keynote educational presentations and shorter informa-tional addresses by many companies in attendance. The show-case format helped foster interaction between attendees seeking solutions and a wide array of industry leaders able to lend theirexpertise in person.

“[At other shows] you get lost between the drill bits and thecutting oil,” said Mike Klos, general manager of Midwest opera-tions for IPG Photonics in Novi, Mich., at last year’s event. “If you’ve ever looked at a laser application, this is the rightplace to come. Everybody’s here.”

37

CUSTOM MANUFACTUREROF PRECISION OPTICS

Reflecting Precision and Quality since 1947.

Extensive in-house coating capabilities on prototypes to high-volume quantities. Let us quote your next project!

LENSES ACHROMATS WINDOWSPRISMS WEDGES

MIRRORS

ISO 9001:2008p p y

ITAR Registered and Compliant

www.lacroixoptical.com870-698-1881 Batesville, AR

Made in the U.S.A.

f

Photonics Spectra July 2012

FASTTRACK

712FastTrack_Layout 1 6/25/12 3:43 PM Page 37

BUSINESSBRIEFSIdex Buys Precision Photonics Idex Corp. of Lake Forest, Ill., has acquired optical compo-nents maker Precision Photonics Corp. (PPC) for $20 million in cash. PPC was founded inBoulder, Colo., in 2000 by scientists-turned-engineers from the neighboring NIST and JILAresearch institutions. It specializes in opticalcomponents and coatings for scientific research,aerospace, telecommunications and electronicsmanufacturing applications. PPC will operate in Idex’s Optics and Photonics platform withinthe Health and Science Technologies segment,joining Semrock and AT Films, which were ac-quired in January 2011, and CVI Melles Griot,which Idex bought in June 2011.

MetaStable Instruments Awarded PatentMetaStable Instruments Inc. of St. Peters, Mo.,has received US Patent No. 8,139,234 for atechnique that measures very low absorption in certain thin-film optical coatings that are de-posited in a vacuum chamber. The technique,which helps coaters more quickly minimize theabsorption in high-power laser and ultrasensi-tive optical applications, was developed under a Missile Defense Agency Phase II Small Busi-ness Innovation Research contract from the USAir Force Research Laboratory at Wright-Patter-son Air Force Base. It was first demonstrated at Deposition Research Laboratories Inc. of St. Charles, Mo. MetaStable Instruments manu-factures patented beam steerers.

WaveTec Vision Raises $16M WaveTec Visionof Aliso Viejo, Calif., has closed a $16.5 millionfinancing round to commercialize its ORA System diagnostic device for cataract surgery.The round was led by new investor Burrill & Co. WaveTec Vision’s previous investors alsoparticipated in the round, including VersantVentures, Accuitive Medical Ventures, De NovoVentures and Gund Investment Corp. The ORASystem uses proprietary Optiwave technologywith a precise light source that enhances thequality of the wavefront image to improvemeasurement accuracy and ensure better patient outcomes. Privately held WaveTec Visionprovides intraoperative wavefront measurementtechnology for refractive cataract surgery.

Schott Meets Congress Schott North AmericaInc. of Elmsford, N.Y., has met with US congres-sional leaders to discuss the importance of theoptics industry to the country and ways in whichCongress can spur job creation in the industryand support its critical high-technology manu-facturing and growth. The visits are part ofSchott’s involvement with SPIE in hosting theannual “Congressional Visits Day” to raiseawareness of and support for science, engineer-ing and technology at the federal level. SchottDefense specifically met with congressionalleaders to advance investment in military glassand optics technology.

UDC to Provide OLED Materials UniversalDisplay Corp. (UDC) of Ewing, N.J., will provideits UniversalPHOLED phosphorescent organicLED (OLED) materials to the Germany-basedFraunhofer Institute for Photonic MicrosystemsIPMS, Center for Organic Materials and Elec-

tronic Devices Dresden (COMEDD) to drive energy efficiency in its white OLED lighting panels. In the two-year agreement, COMEDDwill develop and fabricate energy-efficient whiteOLED panels for market development. The UniversalPHOLED technology enables develop-ment of low-power and eco-friendly displaysand white lighting.

Advanced Photonix Secures Contract Ad-vanced Photonix Inc. of Ann Arbor, Mich., hasreceived a follow-on, 21-month, $1.5 millioncontract from the US Air Force to provide tera-hertz process control instrumentation to supportF-35 joint strike fighter production. The contractis a commercialization pilot program award toensure the quality of specialty stealth coatingsapplied by Northrop Grumman to a subsystemon the F-35. Once completed, the system willconsist of the T-Ray 4000 control unit, which isconnected to a miniature terahertz transceivervia a flexible umbilical up to 100 m in lengthmounted onto an existing robot arm within apaint booth.

JAI Acquires TVI Vision To strengthen its posi-tion in the prism-based line-scan camera indus-try, machine vision camera manufacturer JAIInc. of San Jose, Calif., has acquired TVI VisionOy of Helsinki. Terms of the agreement werenot disclosed. Under JAI’s umbrella, TVI Vision,a manufacturer of line-scan cameras for indus-trial machine vision applications, will continueto operate as an independent entity with its ownsales channel and production base in Helsinki.The company will contribute to the JAI businesswith a complete product portfolio, along with itstechnology, customer bases and employees.

Fluoptics Opens US Office To market and sellits offerings for preclinical in vivo fluorescenceimaging, Grenoble, France-based Fluoptics hasopened an office in Cambridge, Mass. The com-pany develops solutions that combine a nonra-dioactive fluorescent tracer targeting cancercells with its Fluobeam real-time optical imag-ing system. The device, due to enter clinical trials this year in Europe, is available to the preclinical research market. “We will now workon accelerating the distribution of our preclini-cal instruments in the US and Canada directlyor through key partnerships,” said Odile Allard,CEO of Fluoptics. The technology will illuminatecancer cells in real time during surgery.

Company Licenses Face-Tracking TechBased in San Jose, Calif., DigitalOptics Corp., a wholly owned subsidiary of Tessera Technolo-gies Inc., has licensed its Face Tracker technol-ogy to South Korea-based Cammsys Co. Ltd., a camera module maker focused on the mobilephone market. The technology enables camerasto automatically adjust focus, color and expo-sure settings, optimizing portraits even in chal-lenging conditions. Using face-oriented algo-rithms, the technology instantly detects faces ina camera viewfinder and tracks them movingthrough the image if the camera is rotated orsubjects shift their poses.

Ophir-Spiricon Receives Award Ophir-Spiri-con of North Logan, Utah, was honored as theoutstanding technology business of the year by

f

Photonics Spectra July 2012

FASTTRACK

712FastTrack_Layout 1 6/25/12 3:43 PM Page 38

the Cache Chamber of Commerce at its 2012annual awards banquet at Utah State Univer-sity. “Ophir-Spiricon exemplifies the type ofcompany we want to encourage to stay, growand, in the future, locate in Cache Valley,Utah,” said Sandra Emile, CEO of the chamber.“They represent clean, innovative industry;steady growth; and above-average paying jobswith excellent employee benefits. They also be-lieve in supporting the community.” Ophir-Spiri-con, a Newport Corp. brand, develops preci-sion-based laser measurement equipment.

Clinical Trial Next for Laser Technique CarlZeiss Meditec AG of Dublin, Calif., and Jena,Germany, has received conditional approvalfrom the FDA to initiate a clinical trial for itsReLEx smile procedure to correct myopia. Thetechnique for refractive surgery combines fem-tosecond laser technology and precise lenticuleextraction for minimally invasive laser visioncorrection in a single system, the VisuMax fem-tosecond laser. In lasik procedures, the excimerlaser vaporizes tissue, while the ReLEx smilemethod generates a refractive lenticule in theintact cornea with the femtosecond laser. Thesurgeon then removes the lenticule through asmall incision without having to move the pa-tient to an excimer laser.

Femtolaser Approved for Cataract SurgeryIllinois-based Abbott’s iFS advanced femtosec-ond laser has received FDA clearance for use incorneal and cataract surgeries to create bow-shaped or curved arcuate incisions. The fifthgeneration of IntraLase technology, the iFS lasercreates lasik flaps and performs other cornealincisions. The device allows surgeons to makeprecise, bladeless arcuate incisions and to cus-tomize each incision. The placement, length,depth and radius of curvature can influence the surgeon’s desired change to the cornea.These parameters are often difficult to controlthrough traditional incisions using surgicalknives.

Schneider Kreuznach Expands into LEDsWith almost 100 years of optical design experi-ence, Schneider Kreuznach of Bad Kreuznach,Germany, has expanded into the LED marketwith the development of a state-of-the-art lightengine. The new fiber light ultra-LED engine 6was designed to couple light efficiently into afiber bundle. Fabricated around a high-bright-ness LED source, the device delivers 1200-lmflux for 6-mm-diameter active fibers, making itsuitable for medical applications where small-diameter lightguides are commonly used.

Hamblin, Lavery Join Hologenix BoardBased in Santa Monica, Calif., Hologenix LLC,maker of Celliant technology, has completed itsscience advisory board with the appointments ofDrs. Michael R. Hamblin and Lawrence A. Lav-ery. It also has established a research and de-velopment laboratory. With more than 30 yearsof experience, Hamblin is the principal investi-gator at the Wellman Center for Photomedicineat Massachusetts General Hospital in Cam-bridge and an associate professor of dermatol-ogy at Harvard Medical School. He is also amember of the affiliated faculty of the Harvard-MIT Div. of Health Science and Technology.

Lavery is a professor of surgery at the Universityof Texas Southwestern Medical Center.

SBIR Hall of Fame Inductee Sensors Unlim-ited, part of Goodrich Corp.’s ISR Systems busi-ness, has been inducted into the Small BusinessAdministration’s Small Business Innovation Re-search (SBIR) Hall of Fame. A member of thecompany’s team accepted the award April 24 at the White House executive office building.The awards are given to firms with a long period of success in research, innovation and

commercialization. With SBIR funding, SensorsUnlimited has developed shortwave-infrared imager technology for military, industrial andmedical applications. Goodrich Corp. of Char-lotte, N.C., supplies systems and services to the aerospace and defense industries.

B&W Tek Receives Patent B&W Tek Inc. ofNewark, Del., has been awarded US Patent No.8,135,249 for a fiber optic probe that mountsdirectly above the objective lens of a microscopeto add spectroscopic function with minimal

39

f

Of course it fi ts.But it also rocks.

Design in FLIR Quark to your handheld device because it’s the world’s smallest thermal camera. You’ll deliver thermal imaging that “rocks” because Quark comes from FLIR – the industry leader in innovation, performance, reliability and price.

Quark: Actual Size

805.690.5097for FLIR OEM

See Quark in 3D at www.FLIR.com/QuarkPS

Photonics Spectra July 2012

FASTTRACK

712FastTrack_Layout 1 6/25/12 3:43 PM Page 39

alteration to the optical path. The probe andmicroscope can perform Raman and fluores-cence analysis as well as microsampling usingeasily reconfigurable excitation wavelengths.This is the company’s 18th patent since its establishment in 1997. It produces optical spec-troscopy, laser instrumentation and portable/lab-grade Raman systems.

Cooke Corp. Becomes PCO-Tech To better reflect its relationship with PCO AG of Kelheim,Germany, Cooke Corp. of Romulus, Mich., haschanged its name to PCO-Tech Inc. The com-pany will continue to operate under its currentstructure. It also will continue to provide high-speed imaging and lighting systems, CCD andCMOS imaging systems, optical noncontactmeasuring and monitoring instrumentation, andNIST-traceable light-measurement instrumenta-tion and services.

Flir Awarded $18M for Imaging SystemsThe US Navy Expeditionary Combat Commandhas awarded Flir Systems Inc. of Wilsonville,Ore., a $17.9 million delivery order for itsSeaFlir maritime imaging systems for US Navypatrol boats. The SeaFlir line is deployed forsearch and rescue, interdiction, intelligence,surveillance, reconnaissance and targeting application missions. The systems are designedfor operation in the harshest maritime condi-tions. Work for this contract will take place atthe company’s Billerica, Mass., facility. Deliver-

ies are expected to begin in the third quarter of this year. Flir supplies sensor systems that enhance perception and awareness.

LIA, OSHA Renew Alliance The OccupationalSafety and Health Administration of Washingtonand the Laser Institute of America of Orlando,Fla., have renewed their partnership for twomore years to reduce and prevent worker expo-sure to laser beam and nonbeam hazards in industrial, research and medical workplaces.The organizations will develop fact sheets withquestions that should be asked at facilities thatuse lasers and will conduct laser safety seminarsfor OSHA field staff. They also will share infor-mation on laser regulations and standards, theeffects that lasers have on the eyes and skin,laser control measures and laser safety programadministration.

ASE Optics Europe Opened In Barcelona,Spain, ASE Optics Europe was launched tostrengthen the European presence of RochesterPrecision Optics (RPO) and its subsidiary ASEOptics, both of West Henrietta, N.Y. The newfirm’s opening is in response to the growing demand for optics and photonics as enablingtechnologies in Europe. It will provide opticalengineering and design for companies specializ-ing in biotechnology, medical devices, and in-dustrial and automotive technology. The officewill offer ASE Optics’ Discovery Service – 20hours of engineering for a set price – which

can determine feasibility, define a problem oridentify a solution to a well-defined problem.

Company Certified as DoD Supplier ZephyrPhotonics of Zephyr Cove, Nev., has receivedaccreditation as a Category 1A Trusted Sourceby the Defense Microelectronics Activity (DMEA),the highest designation awarded by the US De-partment of Defense (DoD). The certificationrecognizes the company as a trusted supplier of foundry microelectronics goods and servicesto the DoD and other end users within the USgovernment. Achieving this status assures theDoD and prospective defense customers thatthe company’s solutions meet the highest stan-dards of control and security. Zephyr has servedthe defense community for more than 25 years.

Spectranetics Device Wins Approval Spectra-netics Corp. of Colorado Springs, Colo., has received FDA approval for its GlideLight LaserSheath for cardiac lead removal. GlideLight re-quires 55 percent less force to advance than thecompany’s SLS II laser sheath, which, in turn,needs significantly less force to advance thanmechanical telescoping sheaths. “Mechanicalforce is a leading cause of complications duringlead extraction, and reduced force improves thecontrol for safely removing leads,” said Dr.Bruce Wilkoff, director of cardiac pacing andtachyarrhythmia devices at Cleveland Clinic,and a nonpaid member of Spectranetics’ med-ical advisory board.

40

f

Photonics Spectra July 2012

FASTTRACK

712FastTrack_Layout 1 6/25/12 3:43 PM Page 40

GreenLightLED-like solar cell absorbs,emits lightA new solar cell de-

signed to be morelike an LED, able to

emit light as well as absorbit, could achieve efficienciesclose to 30 percent. Typicalsolar cells theoretically canharvest about 33.5 percent of energy from sunlight, butscientists have yet to reachthis efficiency.

Since 1961, scientists haveknown that, under ideal con-ditions, solar cells at mostwill absorb and convert 33.5percent of electrical energyfrom incoming sunlight. Yetfor five decades, researchershave been unsuccessful inachieving this efficiency: As of 2010, thehighest anyone had reached was just morethan 26 percent.

Professor Eli Yablonovitch and col-leagues at the University of California,Berkeley, conducted research to under-stand why such a significant gap remainsbetween the theoretical limit and the lesserlimit that researchers have achieved. Whatthey discovered was a relatively simple, if perhaps counterintuitive, answer basedon a mathematical connection between absorption and emission of light.

“Fundamentally, it’s because there’s a thermodynamic link between absorp-tion and emission,” said Owen Miller, a graduate student at UC Berkeley and a member of Yablonovitch’s group.

Designing solar cells to emit light, sothat photons do not become “lost” within a cell, has the natural effect of increasingthe voltage produced.

“If you have a solar cell that is a goodemitter of light, it also makes it produce a higher voltage,” Miller said, adding thatthis would increase the amount of electri-cal energy that can be harvested from thecell for each unit of sunlight.

Photovoltaic manufacturer Alta De-vices, co-founded by Yablonovitch, used

Photonics Spectra July 2012

A Passion for Precision.

iChrome MLE (4 color multi laser engine,COOLAC technology inside)

iChrome TVIS (488nm – 640nm tunable visible)

www.toptica.com/multicolor

Microscopes and cytometers depend on high-end multi-color illumination systems. Reliability, high intensity and compactness combined with ease of use are a must for these instruments. TOPTICA’s multi-color solutions offer highest power and unmatched stability, for example by proprietary COOLAC technology.

Take only one box – and enjoy up to four colors.

A Passion for Precision.

Take One Fo(u)r All

Multi Color @ TOPTICA

this concept to create a prototype solar cellmade of gallium arsenide. The prototypebroke efficiency records, jumping from 26 to 28.3 percent. Designing the cell toallow light to escape from it as easily aspossible was one reason for the increase.

“What we demonstrated is that the bet-ter a solar cell is at emitting photons, thehigher its voltage and the greater the effi-ciency it can produce,” Yablonovitch said.

The team presented its findings atCLEO:2012, the Conference on Lasersand Electro-Optics, in San Jose, Calif. l

A high-efficiency solar cell by Alta Devices. Courtesy of Alta Devices.

ErratumThe article “Full spectrum boosts solarcell power” (GreenLight, May 2012, p. 39) contained a factual error. Harry Atwater of California Institute of Technology and his colleague AlbertPolman of the FOM Institute forAtomic and Molecular Physics in Amsterdam did not claim to haveachieved solar-cell efficiency of 70percent. The researchers say that suchgoals are realistic and potentiallyachievable, but that the milestone hasnot yet been achieved.

712GreenLight_Layout 1 6/25/12 3:45 PM Page 41

All-Fiber Probes Hold Promise for Medical Imaging Applications

Optical fiber components have beenwidely used in optical communi-cation, fiber laser systems, fiber

optic gyroscopes and fiber sensing appli-cations. Recently, fiber optic probes havebeen adopted for in vivo optical imagingof internal tissues via optical coherent to-mography (OCT), a technology used formorphological imaging of biological sys-tems such as the retina, vasculature andgastrointestinal tract.1 OCT interferomet -

rically measures the phase delay of an injected light beam2,3 onto a measured surface. As a result, the cross-sectional internal microstructure of architecturalmorph ology can be “visualized” at highresolution in micron scale.

The main advantages of using fiberoptic probes in OCT are: (1) high spatialresolution at the micron level, wherein theoptical resolution is mainly determined bythe numerical aperture of the focusing ob-

jective; (2) cost-effectiveness, thanks tohigh-volume manufacturing at low costvia fiber fusion technology; and (3) tech-nological flexibility with measurement in either time or frequency domain or via 1-D1,4 or 2-D5,6 methods.

Implementation and fabrication of theseprobes require stable and well-controlledfiber fusion and glass processing technolo-gies. Automation is a must for consistentand cost-effective mass production of such devices. Furthermore, precision fibercleaving enables the accurate, clean andcost-effective cuts required for creatingthe fiber image guides used in differentvarieties of endoscopes.

Fiber optic probesFor medical imaging applications, fiber

optic devices can be categorized as 1- or2-D probes. Measurements usually aremade either coherently via an interferom -eter to obtain the phase information or incoherently to acquire the intensity infor-mation. In OCT imaging, 1-D coherentfiber optic probes deliver a focused beamto the surface of an internal organ to makea point-wise measurement of the phase ortime delay of the delivered beam relativeto its reference beam. Figure 1 is an illus-tration of this type of probe for OCT im-aging. To extract the 3-D morphologicalinformation, the probe is rotated andpulled back simultaneously; 3-D imag -ing of the internal structure can then be realized.

Figure 2 shows an example of this typeof optical probe. Typically, light at awavelength of approximately 1300 nm isdelivered from a superluminescent light-emitting diode source through a single-mode fiber. The beam is expanded via asection of graded index (GRIN) fiber lens.

42 Photonics Spectra July 2012

Optical fiber probes are still in the early stages of manufacturing, but filament fusion technology enablesmany probe designs, from ball lenses to fiber lenses, among others. Cleaving fiber bundles with high qualityand good throughput facilitates their manufacturing and provides a cost-effective solution for device makers.

BY JEAN-MICHEL PELAPRAT AND DR. BAISHI WANG, VYTRAN LLC

Figure 1. A “window” view of a 1-D fiber optic probe inside an artery. Images courtesy of Vytran LLC.

Figure 2. A schematic of a 1-D fiber optic probe.

712_Feat_Optics4HealthCare_Layout 1 6/25/12 3:39 PM Page 42

The beam is deflected by a mi-croprism mounted at the end ofthe fiber tip and is then deliv-ered to the surface being ana-lyzed. The beam reflected fromthe surface is re-collected bythe probe and coupled backinto the fiber. This beam ismade to interfere with a refer-ence beam so the phase or timedelay information can be ex-tracted. Via this method, themorphology of the internalorgan surface can be quantita-tively measured. Spatial resolu-tion of the measurement is de-termined by the spot size of thefocused beam, usually around afew microns. A variation ofthis type of probe includesusing a different GRIN lensand adding a spacer (usually corelessfiber) between the GRIN lens and the opti-cal fiber. Multiple GRIN lenses can beused to achieve different optical propertiesof the output beam.

Fabricating probesThe key optical properties of a fiber

optic probe similar to the one shown inFigure 2 are focusing spot size and work-ing distance, both of which are determinedby the numerical aperture and aberration

introduced by the focusing lens. In addi-tion, any backreflection from the opticalinterface must be suppressed to enhancethe signal-to-noise ratio. Mechanically, the probe has to be rugged for long-termstability and immune to vibration.

It is preferable to make this type ofprobe all-fiber using high-quality fusionsplicing rather than the conventional free-space optics approach. This provides somedistinct benefits: First, an all-fiber probedoes not require any alignment; it is also

more compact. Second, a fu-sion-spliced fiber joint signifi-cantly reduces the backreflec-tion and improves the trans - mission efficiency. As a result,a better measurement signal-to-noise ratio can be achieved.Third, an all-fiber device ismore rugged and intrinsicallyimmune to ambient mechanicalvibration and temperaturechange. Overall, it is more reliable, consistent and cost-effective.

Optically, the quality of thefocusing beam is crucial forthe imaging system to main-tain high spatial resolution andgood measurement sensitivity.For an all-fiber device, thistranslates to a need for uni-

form heating around the fiber during thefusion process to maintain good beam cir-cularity. Also, the GRIN fiber length mustbe precisely controlled to deliver the de-sired optical properties of the exit focus-ing beam.

When fabricating these fiber opticprobes, filament fusion technology (Fig -ure 3), which is based on resistive heating,provides several advantages. First, the fila-ment has a circular shape, which main-tains a uniform temperature circumferen-

43Photonics Spectra July 2012

Figure 3. A schematic of the filament fusion process.

Figure 4. Left: A schematic of several sections of fiber fused together. Right: A side view shows actual fused fibers spliced using filament fusion and precise length control of the fibers.

Figure 5. Left: A fiber optic probe with a ball lens at the tip. Right: A complete all-fiber probe with capillary tube encapsulation.

712_Feat_Optics4HealthCare_Layout 1 6/25/12 3:39 PM Page 43

tially and therefore leads to uniform heat-ing around the fiber. Second, filament fusion offers temperature control over awide range, which is important for pro-cessing different types of fiber with vari-ous optical characteristics or doping con-centrations. Third, filament fusion ishighly consistent and repeatable. Thistranslates to a stable process and high production consistency and yield. Fourth,filament fusion produces a strong splicebetween fibers with splice strength typi-cally exceeding 200 kpsi. This ensureslong lifetime and robustness of the probe.

During the fusion process, control ofthe GRIN fiber length is critical to achiev-ing the desired optical characteristics ofthe output beam. Position registry betweenfiber splicing and cleaving is required toprecisely control the length of each splicedfiber pair. Figure 4a schematically showsseveral sections of fibers that are splicedtogether; Figure 4b is the side-view imageof four sections of fibers with differentfiber lengths spliced together. The outputfiber is cleaved at an angle to suppressbackreflection.

Figures 5a and 5b show additional ex-amples of fiber optic probes. The formershows a fiber optic probe with a ball lens

tip; the latter, an encapsulated probe withseveral fiber elements spliced together in-side the capillary tube.

Image guidesIn addition to using the 1-D pointwise

fiber probe for OCT, the fiber bundle, con-sisting of several thousands of micron-level fibers compactly arranged together,is often used as an image guide for 2-Dcoherent imaging.6

Figure 6 is a schematic of such a fiberimaging system based on a Michelson in-terferometer configuration. The measure-ment typically is made in time domainusing a broadband source or in frequencydomain using a tunable swept laser sourceto extract the 2-D phase information.

One important aspect for producing thistype of system is how to process the endface of the fiber bundle, which works as a pathway to transmit thousands of lightbeams through. High optical quality of thebundle end face is critical to ensure goodvisibility of the interference fringes andtherefore good performance of the system.Polishing is typically used for producing ahigh-quality flat surface on the bundle endface. However, this is labor-intensive andtime-consuming, and polishing tends to

44 Photonics Spectra July 2012

Fiber Optic Probes

Figure 7. A schematic of the tension-scribe fiber-cleaving method.

Figure 6. A 2-D coherent fiber bundle imaging setup based on Michelson interferometry.

712_Feat_Optics4HealthCare_Layout 1 6/25/12 3:39 PM Page 44

have a rounding effect around the edge,which could compromise surface flatness.

Alternatively, advanced fiber-cleavingtechniques, such as the tension-scribemethod, can be used to produce a mirror-like flat end face on fibers with various diameters. The tension-scribe fiber cleav-ing method is schematically shown in Fig-ure 7. During the cleaving process, a pre-determined tension (based on the fiber’sdiameter) is applied to generate tensilestress in a longitudinal direction. A bladescribes the fiber vertically from the side tocreate a crack. When a large enough crackforms, the fiber can be cleaved to producea clean, high-quality fiber end face. Em-bedded processes can precisely control thecleaving process and make it fully auto-matic. This method requires a special fibercleaver such as the LDC-400 Large Diam-eter Cleaver from Vytran LLC.

The whole tension-scribe cleavingprocess takes less than 30 seconds andproduces a surface with flatness generallybetter than a polished surface. It can alsomaintain a small cleave angle, which min-imizes the deflection of the input and out-put beams. Additionally, low cleave angleis important for high-quality splicing if the cleaved fibers are to be fusion splicedtogether.

This method can be readily used forcleaving image guides, whose size can bemore than 1 mm in diameter with severalthousands of fiber pixels. Figure 8 showsan example of a cleaved bundle. The bun-dle diameter is 670 μm with 10,000 fiberpixel count.

All-fiber based probes have demon-strated technical superiority for both 1-and 2-D optical imaging in OCT applica-tions. Although fiber probes are still in the

early stage of manufacturing, market demand will grow exponentially in theyears to come. Unique filament fusiontechnology is enabling many probe de-signs, from fiber lenses to ball lenses andmany others. The capability of cleavingfiber image bundles with high quality andgood throughput facilitates their manufac-turing and provides a cost-effective solu-tion for device makers. Fully automatedfiber fusion systems based on filament fu-sion and tension-scribe technology couldallow low-cost, high-volume manufactur-ing of these fiber optic probes for medicalapplications.

Meet the authorsJean-Michel Pelaprat is CEO of Vytran LLC,and Dr. Baishi Wang is its director of technol-ogy; email: jmp@vytran.com.

References1. G.J. Tearney et al (1996). Scanning single-

mode fiber optic catheter-endoscope for opti-cal coherence tomography. Opt Lett, Vol. 21,p. 543.

2. J.G. Fujimoto et al (1999). High resolution invivo intra-arterial imaging with optical co-herence tomography. Heart, Vol. 82, p. 128.

3. Y.X Mao et al (2008). Fiber probes used inoptical coherent tomography. SPIE Proc7099, Photonics North.

4. X. Li et al (2000). Imaging needle for opticalcoherence tomography. Opt Lett, Vol. 25, pp. 1520-1522.

5. T.Q. Xie et al (2006). GRIN lens rod basedprobe for endoscopic spectral domain opticalcoherence tomography. Opt Expr, Vol. 14, p. 3238.

6. H.D. Ford and R.P Tatam (2009). Swept-source OCT with coherent imaging fibrebundles. 7503, 20th International Confer-ence on Optical Fibre Sensors, Julian Joneset al, eds.

45

Fermionics

4555 Runway St. • Simi Valley, CA 93063Tel (805) 582-0155 • Fax (805) 582-1623

w w w . f e r m i o n i c s . c o m

Opto-Technology

• Analog bandwidth to 8 GHz.• FC, SC, and ST receptacles.• Active diameter from 50 μm to 5 mm.• Standard and custom ceramic

submounts.• TO-style packages available with flat

AR-coated windows, ball lens anddome lens.

• Standard axial pigtail packages andminiature ceramic pigtail packages,all available with low back-reflectionfiber.

Communications

Instrumention

Medical

Imaging / Sensing

Photonics Spectra July 2012

Fiber Optic Probes

Figure 8. Images of a cleaved fiber bundle with 670-µm diameter: (a) side view of a flat cleave angle; (b) end view of the same cleaved bundle; (c) close-up view of the fiber bundles.

712_Feat_Optics4HealthCare_Layout 1 6/25/12 3:39 PM Page 45

Nanoscale Biomaterials Require Close Observation

BY LYNN SAVAGE,FEATURES EDITOR

S tudying useful materials is not limitedto macroscale structures such as sheetmetal, optical glass, wood or con-

crete. Some of the most exciting workbeing done in materials research these daysis on a much tinier scale and has applica-tions that can get well under your skin.

Polyurethane is already a useful andubiquitous material, found in common ob-jects from skateboard wheels and Spandexto wood sealer and foam insulation. It alsois found in many artificial body parts suchas replacement hip joints – but while it isstrong and lightweight enough for theseapplications, there is much room for im-provement. Furthermore, interest in usingpolyurethane for even finer structures,such as artificial blood vessels and otherreplacement tissues, is growing.

Improved polyurethane-based “nanohy-brids” will be very useful for biomedicalapplications, said Pralay Maiti, coordina-tor of the School of Materials Science andTechnology at Banaras Hindu University’sInstitute of Technology in Varanasi, India.

These amalgamated materials under de-velopment – which can be compared withthe doped crystals used in laser media andin optical glass – could be used to improvethe strength, durability and flexibility ofpolyurethane-based biomaterials, and alsoto add controlled drug delivery to the listof tasks they can perform.

As with many polymers, polyurethanemolecules have the capacity to assembleinto long strands with no external influ-ences. Such self-assembly results in somesynergistic effects, lending them strengthand toughness, Maiti said.

The formation of polymers through self-assembly, however, is still full of mystery,requiring careful analysis through multipletechniques. Some polymers employ hydro-

gen bonds to form stacks of molecule-thick sheets to become flat films useful forbiomaterial engineering. These can be

investigated using various techniques asthey go through several stages of forma-tion. For example, when polymers begin

Photonics Spectra July 201246

Replacement bones and blood vessels are just two types of artificial tissues that require deep-imaging microscopy techniques to develop.

When using atomic force microscopy (AFM) to characterize novel materials,such as artificial biological tissues, there are a few logistical issues concerninginstrument setup and sample preparation.

Dido Yova of the National Technical University of Athens in Greece said that samplepreparation for AFM research is not complicated but noted that there are some cruciallyimportant steps to take:

The type of sample and its size are very important. Sample dimensions must be realisticbecause the majority of AFM stages put constraints on maximum sample size. For exam-ple, a typical AFM stage can hold a sample measuring 50 � 50 � 20 mm, while the maximum horizontal and vertical scan ranges are ~90 �m and 1 to 20 μm, respectively.AFM probes must be able to access sample features directly; e.g., noteworthy features located inside holes smaller than the AFM tip will not be reachable.

Samples must be rigidly mounted to the substrate. If the material is not rigidly adhered,the probe can move the sample material to the edge of the scan range and the image ap-pears as though there is nothing on the surface. Furthermore, fragments from the materialsurface can become attached to the AFM probe, resulting in imaging artifacts.

Samples must be clean. If the surface is dirty, such as with a thick contamination layer,the AFM probe must penetrate the contamination layer to reach the surface, resulting indistortions in the final image.

Samples and their substrates must be mounted tightly to the AFM stage. Loose fittings willmake the system more prone to vibrations that reduce the resolution of the microscope.

Getting the most mileage out of atomic force microscopy

Transmission electron microscopy image of a poly-urethane nanohybrid, showing the dispersion oftwo-dimensional nanoclay within the polyurethanematrix. Courtesy of the American Chemical Society.

Differential interference contrast microscopy revealsthe ability of cells to adhere to the nanohybrid sub-strate. Courtesy of the American Chemical Society.

712_MaterialsFeat_Layout 1 6/25/12 3:38 PM Page 46

as molecular planes stacked together viahydrogen bonds, researchers use small-angle neutron scattering and x-ray diffrac-tometry analysis. When one polymer progresses to its next stage of formation,atomic force microscopy becomes useful.When polymers at this stage begin to accumulate into tiny clusters discernible as crystallites, they can be viewed by optical microscopes.

Ultimately, improving polyurethane andsimilar polymers by “tuning” them withadded materials will depend upon usingthe right analytical tool.

Turning polyurethane into a biomate-rial useful for becoming substitute veins, arteries or other fine tissues will dependon adding dopants that not only increasestrength and toughness, but also help thematerial hold onto living cells. The poly-mer is the scaffold upon which living tissues are hosted. The added material thatMaiti’s group is focused on is a derivativeof montmorillonite, or magnesium alu-minum silicate, which the researchers call“nanoclay.”

The nanoclay substance is added priorto the two-step process used to createfresh batches of polyurethane. In the first step, a prepolymer material – plusnanoclay – is prepared. The second step,which controls strength and durability, is the extension of the linking polymericchain via materials such as hydroquinoneor biphenol.

“The main purpose of chain extension is the reaction of unreacted di-isocyanateswith diols, which results in the higher molecular weight of the polyurethanes,”Maiti said. His group used a series ofchain extenders to test their effect on the properties of the final polyurethane/nanoclay development.

To examine the various versions ofclay-infused polyurethane, Maiti and hiscolleagues turned to various microscopytechniques. They used a polarizing opticalmicroscope made by Leitz (now part ofLeica Microsystems of Wetzlar, Germany)to examine the sheet’s surface morphol-ogy, capturing its finely segmented struc-ture. An atomic force microscope made by NT-MDT Co. of Moscow and set intapping mode determined the domainstructure of the sheets, indicating the sizeof hard-segmented zones created with the added nanoclay.

A scanning electron microscope fromTokyo-based Hitachi High-TechnologiesCorp. showed the surface morphology athigher magnification than an optical mi-croscope provides, Maiti said, and x-rayand small-angle-neutron scattering tech-niques helped reveal the intricacies oflayer spacing and of larger assembliesmade up of several molecular sheets, respectively.

Lastly, the group used a transmissionelectron microscope made by FEI Co. ofHillsboro, Ore., to study the dispersion

of two-dimensional nanoclays within thepolyurethane molecular matrix.

“The unique feature of this work is thatwe could capture every possible step ofthe self-assembly phenomena, startingfrom molecular sheet (nanometer dimen-sion) to bigger agglomerates (micronscale) using those imaging and scatteringtechniques,” Maiti said.

Building collagen scaffoldsAnother major target of biomaterial

engineers is collagen, the most abundantprotein found in people. Collagen is abasic component of the extracellular matrix – the “backing board” that holdscells together in a swatch of tissue – and it possesses unique properties, includingnegligible cytotoxic response and readyavailability – that make it widely used as biomaterial.

“The value of collagen as biomaterialhas led research on [its] use in scaffoldsfor ligament repair, collagen grafts for scar and burn repair, and the engineeringof osteochondral tissue,” said Dido Yova,director of the Biomedical Optics and Applied Biophysics Laboratory at the National Technical University of Athens in Greece. As with polyurethane, collagenis a candidate material for repairing or replacing heart valves and bones.

To work well within the body, collagen,polyurethane and similar materials mustbe biocompatible and characterized from

47Photonics Spectra July 2012

Top left: Collagen fibers formed on mica surface. Top right: The atomically flat surface of a freshly cleaved mica substrate. Bottom: The D band (67 and100 nm) as it was imaged in collagen fibrils on mica. Courtesy of Dido Yova,National Technical University of Athens.

Topographic images of polystyrene particle surfaces (PPS) used as potential AFMsubstrate. On top are representations of the hexagonal packing of the particles.Courtesy of Dido Yova.

712_MaterialsFeat_Layout 1 6/25/12 3:38 PM Page 47

controllable processing conditions. Theyalso must be robust and hydrophilic,which helps them support cell attachment.

Yova and her colleagues are working toform collagen-based biomaterials with aneye toward controlling surface characteris-tics, such as roughness and the size andorientation of collagen fibers.

“[Our] aim is to develop nanostructuredcollagen films, while the surface retains thebulk properties of collagen,” she said. “It isvery challenging to understand and controlthe spatial organization of adsorbed proteinlayers, like collagen, in the nanoscale.”

Type I collagen, which is the most common fiberlike form of the material,consists of three amino acid chains thatform rod-shaped triple helixes, which self-assemble into fibrils. Although it is largelyself-assembling, it still is sensitive to theeffects of cellular activities, particularly in young or healing tissues, Yova said. The complex structure of type I collagenpresents as different morphologies in dif-ferent tissues, yielding different functions.This complicates attempts to direct colla-gen formation as well as the design andcreation of artificial structures.

To fully characterize the progression ofcollagen fibril and thin films as they form,Yova and her team chiefly use an atomicforce microscope (AFM) made by Veeco(but manufactured since 2010 by BrukerCorp. of Billerica, Mass.).

Using an AFM for delicate materials re-search is common but presents its own setof setup issues (see sidebar). Choosing theappropriate substrate is important as well,and this task greatly depends on the sam-ples to be imaged. Rough surfaces are notuseful as a substrate material; therefore,

the most widely used materials are glassand mica – especially muscovite mica.

“Mica is one of the smoothest substrates,with a roughness of only ~0.1 nm, and theuse of freshly cleaved mica provides a cleansurface which does not demand a furthermethod for removing contamination,” Yovasaid. Mica is readily available and inexpen-sive, as well as hydrophilic, which is desir-able. By comparison, glass is more thanthree times as rough (0.3 to 0.5 nm). Siliconand highly ordered pyrolytic graphite(HOPG) also can be used. HOPG is veryuseful in some studies because it can bereused numerous times, Yova said, but it ishydrophobic and more costly than the otherchoices. In recent experiments, Yova’s groupalso tested polystyrene beads as a possiblesubstrate material. Polystyrene is transpar-ent, nontoxic, stable and inexpensive.

“AFM is a very powerful technique for studying biomaterials, since it provideshigh-resolution imaging of structure, combined with measurement of surfaceproperties, combined with measurement ofsurface properties and surface-dependentintermolecular interactions under differentconditions,” Yova said.

Her team continues to test varioustypes of substrates and collagen deposi-tion techniques to find the best ways toestablish novel biomaterials from thenanoscale to the macroscale. Its ultimategoal is to fully clarify the roles playedby various parameters and to determinethe best characteristics for collagen-based biomaterials.

“Thin collagen films will be used to in-vestigate cell-biomaterial interactions so asto correlate specific biomaterial nanocharac-teristics with cells’ behavior,” she said.

48 Photonics Spectra July 2012

Biomaterials

See us at Intersolar, Booth #5441 and Optics & Photonics, Booth #1028

Left: A 3-D topographic image (20 � 20 µm via tapping-mode AFM) presenting the aging of PPS after six months, showing a crack 100 nm wide. Top right: The height profile of a single horizontal line from the left previous image. Bottom right: A schematic of how the AFM measures the height of the surface crack. Courtesy of Dido Yova.

712_MaterialsFeat_Layout 1 6/26/12 10:16 AM Page 48

A more useful plaquePolyurethane is a practical and safe arti-

ficial substance, and collagen, a ubiquitousprotein in mammalian structures, but lessbenign materials may also be directed toward helpfulness. Amyloid plaques areknown for confounding neuronal signalsin the brains of patients with Huntington’s,Parkinson’s and Alzheimer’s diseases.These plaques are composed of proteinfibers, but recent research indicates thatthese fibers can be used to help shapenovel biomaterial formation.

Whether naturally occurring or specifi-cally designed, amyloid fibers are goodcandidates for making nanoscale biomate-rials because they efficiently self-assembleinto well-defined structures and are rela-tively inexpensive, said Juan José Valle-Delgado of the Institute for Bioengineer-ing of Catalonia near Barcelona, Spain.Valle and his colleagues are using AFMand a technique called single-moleculeforce spectroscopy to suss out the bestway to use amyloid fibers, or fibrils, tosupport new nanostructures.

AFM’s combination of high sensitivityand the ability to operate in liquid envi-

ronments was attractive to Valle’s team for the characterization of the fibrils. Theresearchers considered transmission elec-tron microscopy (TEM) as well, but thattechnique requires samples to be dried,which could affect the way in which theproteins change shape (conformation); it also could affect the final structure ofthe assembled fibril. Cryo-TEM can avoidthat uncertainty, Valle said, but many images must be processed to obtain ahigh-resolution computer reconstruction.

With AFM, he noted, the tip geometry isan important factor that affects the resolu-tion. Horizontal dimensions are usually over-estimated in AFM images because of the tipgeometry, but vertical dimensions are veryprecise, he added. In the case of soft sam-ples, such as amyloid fibrils, scanning withthe tip must be done very carefully to pre-vent damaging the sample, which is some-times very tricky in liquid environments.

The investigators used a Veeco AFM tostudy the self-assembly of amyloid fibrilsderived from the human peptide hormoneamylin. Unlike Yova’s group, Valle and hiscolleagues chose HOPG as the appropriatesubstrate material. They cleaved the

49Photonics Spectra July 2012

Biomaterials

AFM images show self-assembled wild-type (C-WT) and reverse-sequence (C-RETRO) human amylin duringformation of fibrils. Fibrils growing on top of a dense pack of other protofibrils are indicated by arrows (c).Courtesy of Soft Matter, a journal of the Royal Society of Chemistry.

712_MaterialsFeat_Layout 1 6/25/12 3:38 PM Page 49

HOPG slab prior to depositing the sampleto obtain the cleanest, smoothest surfacepossible.

“Highly oriented pyrolytic graphite is aquite smooth substrate,” Valle said. “How-ever, unlike hydrophilic mica, HOPG is ahydrophobic substrate. The hydrophobicnature of HOPG could favor the adsorp-tion of hydrophobic peptide aggregates.”

The group used the Veeco AFM to characterize the surface of the massing fibrils, but turned to a different instrument,made by Asylum Research of Santa Bar-bara, Calif., to analyze the force binding the peptides together as they lay on a hydrophilic mica substrate. “Force spec-troscopy” or “single-molecule force spectroscopy” are names used in the AFMcommunity for a technique that measuresthe binding forces between molecules ofinterest – for example, between an anti-body and an antigen – or to analyze themechanical properties of polymeric bio-molecules such as proteins when they arestretched.

Any AFM model can obtain both im-ages and force measurements, but there isa subtle difference between the two instru-ments, Valle said.

“The Asylum Research AFM was pre-ferred for force measurements because it is better designed to avoid drift whenmoving over the substrate to collect forcecurves [at] different points,” he said.

Both techniques showed the researchersthat amyloid fibrils could be used as tem-plates for nanoscale wires, with potentialapplication as guides for nerve cell growthor as scaffolds for bone reconstruction.Future work by biomaterial researcherslikely will be found in a wide range of re-placement parts in everyone’s body.

50 Photonics Spectra July 2012

Biomaterials

Lynn Savagelynn.savage@photonics.com

AFM images show real-time deposition of RETRO protofibrils. Courtesy of Soft Matter, a journal of the Royal Society of Chemistry.

712_MaterialsFeat_Layout 1 6/25/12 3:38 PM Page 50

With over 150 R&D staff, and more than 500 Zygo patents supporting him, Dan Musinski, Zygo Director of Interferometer Marketing, is the man out front, understanding your application and making metrology systems that solve it. IR, EUV, and large aperture interferometers, Dan has seen it all.

With over 10,000 installed metrology systems, Zygo is a byword for reliability and precision. No one makes more interferometric systems than we do. And we make them to suit all needs.

To solve a measurement challenge, you need to talk to the experts. People like Dan Musinski. He’ll say,

“Welcome to Zygo.”

metrology you trust,from people you can trust to solve your next applications

Standing over eight feet tall and weighing more than 2500 pounds, this high precision metrology workstation is a custom Zygo solution. Call Zygo with your special metrology needs.

1-800-ZYGO-NOW www.zygo.com/trust interferometers@zygo.com

Zygo is a leading manufacturer of inteferometers and optical surface metrology systems. Contact us today to discuss your extreme precision and uniquely demanding measurement requirements.

712_Zygo_Pg51_Layout 1 6/25/12 4:10 PM Page 51

DPSS Lasers Give Medical Device Manufacturing an Edge

Medical device manufacturing is becoming more challenging everyday as more functionality and

features are added to the injectors, pumps,implants and other devices used to keeppeople healthy. There is a growing needfor smaller devices with precise, high-quality, tiny features, and techniques beyond those found in traditional manu-facturing are required to meet the chal-lenge. Laser processing has been fillingthe need for quite some time; today, lasersare routinely used for marking, cutting and drilling of various materials duringmanufacturing of medical devices.

With almost anything related to humanhealth, there are stringent requirements formaterials and methods, and this is no lesstrue for medical device manufacturing.The materials tend to be of high strength,

purity and chemical resistance, often mak-ing them difficult to fabricate and process.They also run the gamut of material types– corrosion-resistant and high-strengthmetals such as stainless steel and titanium;high-strength ceramics such as zirconiaand alumina; and an entire class of med-ical-grade polymers composed of variousTPUs (thermoplastic polyurethanes), poly-carbonates and fluoropolymers such asPTFE (Teflon). Not only must the materi-als be extremely pure, but manufacturingprocesses such as drilling and cutting mustbe as clean as possible – leaving behindminimal debris and residue – to minimizethe need for costly and time-consumingpostprocessing.

The laser marketplace for medical de-vice manufacturing continues to be domi-nated by the high-average-power CO2 and

the high-pulse-energy excimer. However,as devices (and, therefore, features) con-tinually shrink and become increasinglyspecialized – which leads to lower produc-tion volumes – these lasers are proving tobe unsuitable in some cases. Furthermore,with the high cost of ownership often associated with such lasers, medical device manufacturers are eager to find alternatives.

The performance of Q-switched diode-pumped solid-state lasers spans a largeand growing range of powers, wave-lengths and pulse durations, which is helpful in addressing the myriad materialsused in medical devices. In addition, asthis laser technology continues to advance,products are seeing significant improve-ment in the areas of packaging, upfrontand ownership cost, ease of use, and –perhaps most important of all – reliability.

One example of a Q-switched DPSSlaser system is the Spectra-Physics Ex-plorer line, which includes 1064-, 532-and 355-/349-nm wavelengths at averagepower levels from 50 mW to 5 W – allwithin a narrow range of nanosecondpulse durations (~5 to 20) and in a com-pact design. Versions are optimized for (1) a low pulse repetition frequency (PRF)and high-pulse energy regime for the mostdifficult-to-machine materials – which isused in the first example below of catheterlaser drilling – and (2) at lower pulse energies but higher PRFs, enabling fastexecution of less energy-intensive pro -cesses – which is used in the second example be low of laser marking medicaldevices.

Laser drilling for cathetersA common medical device manufactur-

ing process that uses lasers is catheterhole-drilling and skiving, in which open-ings in catheter tubes are machined. Theseopenings are used for venting, drug deliv-ery and electrical wire conduit. Key re-quirements include little or no residual de-bris and very smooth edges to the featuresafter laser processing is completed. Often-times, the tubing material is a polymerthat may be difficult to machine cleanly.

52 Photonics Spectra July 2012

With a wide range of wavelengths, short pulse durations, high average powers and high pulse energies, compact and cost-effective diode-pumped solid-state (DPSS) lasers have a promising future in medical device manufacturing.

BY JIM BOVATSEK, JÜRGEN NIEDERHOFER ANDDR. RAJESH S. PATEL, SPECTRA-PHYSICS

Figure 1. The power, pulse energy and pulse duration of a typical Explorer 349 laser system. Q-switcheddiode-pumped solid-state lasers have a large and growing range of powers, wavelengths and pulse durationsto address the various materials used in medical devices. Images courtesy of Spectra-Physics.

712_Feat_SpectraPhysics_Layout 1 6/25/12 3:41 PM Page 52

Materials such as silicone, Teflon, PEEK(polyetheretherketones) and TPUs such asTecothane are commonly used. Requiredhole sizes range from 0.001 to 0.010 in.(25 to 250 μm), and tubing wall thick-nesses are of similar dimension. For high-est quality, lasers with UV wavelengthsand short pulse durations are used.

Recently, Innovative Laser Technolo-gies Inc. (ILT) of Minneapolis was con-tracted by one of its medical device cus-tomers to build a tool for machining suchopenings in polymer tubing. The systemincorporated a 349-nm UV laser alongwith X-Y-Z motion, galvo-based beam delivery and automated machine vision for locating part features prior to drilling.

ILT had stringent requirements for pro-cessing quality, but the throughput targetwas achieved; the compact, capable sys-tem impressed team members, ILT projectmanager Jim Jacklen said. “Another greatfeature was the quick warm-up time. Thisallowed part processing to begin as soonas the system power-up was completed.”

The short pulse widths and high pulseenergy of this type of laser are well suitedto cleanly machine these more difficultmaterials; at 500-Hz operation, it will de-liver ~150 μJ of pulse energy with a 4-nspulse duration (Figure 1). This translatesinto a high peak power (the ratio of thepulse energy to the pulse duration) of >35kW. This is important because, for a fixedoptical spot size, peak power and pulseenergy can be primary determinants forwhether or not a laser ablates a particularmaterial. With the UV wavelength of 349nm, many polymers will strongly absorbthe laser light and will therefore be cleanlyablated by the laser.

Even if the absorption is somewhatweak, however, a combined high energyand short pulse width means that materialprocessing can still proceed without resorting to extremely tight focusing, which can be difficult to accomplish withcommon scanning galvanometer-based systems.

Laser simplicity and size also are im-portant considerations for this application.ILT has been providing laser tools to themedical device industry for many yearsand is uniquely positioned to providetimely customized solutions. In this case,however, the end customer’s time line was too aggressive for a new tool design,necessitating instead that the laser beretrofitted into a larger, more typical work-station for medical device manufacturing.

“In order to meet a compressed projectlead time, an existing system design waschosen that had been used with a differenttype of laser ablation process,” Jacklensaid. That type of laser was significantlylarger than the one selected, so the systemcould have had an even smaller footprint,he added.

The tool and the laser are suitable formachining a variety of features in a vari-ety of medical materials. In particular, the optical delivery system was designedwith high-quality structuring of polymertubing in mind. One such polymer isPEEK, a medical polymer with good me-chanical strength and chemical resistanceover wide-ranging temperatures. Withproper process optimization, the laser machined clean holes in PEEK materialwith 0.003-in. (~80-μm) wall thickness(Figure 2).

The ablation of the polymer also had noapparent swelling or burring of the mate-rial at the edges of the holes, and very lit-

tle residual debris was observed. Com-pressed air was applied during the process,but no cleaning or other postprocessingwas performed on the features. Drillingtime for each hole was ~100 ms.

Marking applicationsMarking of medical devices is another

large application space for lasers. Consid-ering the wide range of materials andmarking dimensions, a variety of DPSSlaser systems can be of use for this appli-cation. In addition, many of these lasersare offered in high-PRF/low-pulse-energyconfigurations, allowing lower-energypulses to arrive at rates of tens of thou-sands to more than 100,000/s for high-speed and “gentle” marking.

Of critical importance for this applica-tion is that the marking process remove aslittle material as possible because this willleave behind the lowest amount of debriscontaminants. This implies that shorter-pulse-duration lasers are a good fit because

53Photonics Spectra July 2012

Figure 2. Laser-drilled openings in smooth (left) and textured (right) surface PEEK polymer. With proper processoptimization, the laser machined clean holes in the medical polymer.

Figure 3. Low- (left) and high- (right) magnification photos of 2-D data-matrix marking in medical polymer. This mark was generated with the Explorer 349 laser with a single-pulse-per-dot process.

712_Feat_SpectraPhysics_Layout 1 6/25/12 3:41 PM Page 53

there is shallower heating in the bulk of thematerial and, therefore, a lower likelihoodof uncontrollable large-volume material removal. This prerequisite also means thata laser pulsing with lower energy but at ahigher PRF will be advantageous from aprocess throughput point of view.

A common marking technique is a two-dimensional data matrix. For materialswith strong absorption and a relatively lowthreshold for ablation, each dot in the datamatrix can be realized with a single pulse.In Figure 3, the 2-D data matrix was gen-erated on a medical polymer with a single-pulse-per-dot process. The relatively highpulse energy can be used to make fairlylarge matrix dots with just a single pulse –in this case, 65 μm in diameter.

Marking time for this type and size offeature is directly related to the laser’sPRF and the speed of the beam scanningequipment, and is typically in the range oftens to hundreds of milliseconds per ma-trix. It is important to note that, with sucha single-pulse marking process appliedover a small area (micromarking), a highlaser PRF does not necessarily result in afaster process because the equipment forscanning the beam commonly cannot sup-port more than a few kilohertz of laserpulsing frequency.

Larger medical implants, includingthose used for orthopedics, are fabricatedwith much harder materials, such as hardceramics. Alumina (aluminum oxide, orAl2O3) has been used for decades in ortho-pedic implants such as hip replacements.In addition, thinner coatings of aluminacan be applied to softer materials to imparthigher strength to the components.

To create a 2-D data-matrix mark in alumina ceramic, a raster scan process was used in which each marked pixel inthe matrix was composed of a group ofclosely spaced horizontal lines (Figure 4).

This material was marked with 1.5 W of power from a 532-nm laser system. The dimension of each filled pixel in thematrix is ~250 μm and was generated with~30-μm raster spacing. Besides the datamatrix marking, the photo also demon-strates the ability for gray-scale marking.In this case, variable contrast is achievedby changing the pulse energy (but with a fixed average power) and the beam scanning speed.

Medical device market outlookMedical manufacturing is a growing

industry that shows no signs of slowing.Physicians and other health professionalsare increasingly teaming up with scientistsand engineers to develop new technologiesfor enhancing and extending human life.

Recent market research indicates world-wide sales of medical devices at $300 bil-lion in 2011.1 The US has the largest med-ical devices market, with estimated salesof roughly $105 billion in 2011.2

The aging population and the increasesin cardiovascular diseases, diabetes, obe-sity and hypertension are the driving fac-tors for the bigger medical device marketin the US. Segments of the medical deviceindustry include instruments used in cardi-ology, oncology, neurology, orthopedic,aesthetic and health care information sys-tems. The drug delivery and implantabledevices account for a large share of themarket for medical devices.

All indicators suggest that medical device manufacturing will continue to be strong for lasers for years to come. Although excimer and CO2 lasers are a large majority of the market today, thetrend toward smaller, more complex andmore highly specialized medical devices isdriving the need for simpler, high-perfor-mance laser solutions.

Meet the authorsJim Bovatsek is applications laboratory man-ager at Spectra-Physics in Santa Clara, Calif.;email: jim.bovatsek@spectra-physics.com. Dr.Rajesh S. Patel is director of strategic market-ing at the same branch; email: raj.patel@spectra-physics.com. Jürgen Niederhofer is generalmanager at Spectra-Physics in Stahnsdorf, Ger-many; email: jurgen.niederhofer@spectra-physics.com.

References1. Zacks Investment Research, www.zacks.com/

stock/news/50398/Medical+Devices+Industry+Outlook+%96+April+2011.

2. Espicom Business Intelligence, www.espicom.com/Prodcat2.nsf/Product_ID_Lookup/00000110?OpenDocument.

54

���������� �����������������������

�������������������������������������������� ����� ��! "���#�$

� �%& �&' �������!���(�!���

�� � )������� �� ��*��+,!�������� ��!���*���-���.����� ��

����!��/*���0����1��!���������!��-��������� �2�������34����!*���!��!��) ���!�!� �)�� �������5�6�)�.447

(������8��������������!��!�������!*���!��!�

�1��!��9������!����:��������������/��� ���!�

������5�������/*���0���������8��;���������!� �)�� ����!������������������/*���0�

��������� ���������������� ��������������������� ������������ ������!��������"#��������"� �� ����$��"��%���������� �������&����$��"��'�"����(�������� �������������'��)����*

���������������� ���������������������������� ����

��� ���������

,�������������� ����

,�����������������

���������������

���������� ��� ������� �

��������������������

6������������������������ �� ����)�!����

��!���:� ��"�����)�� ����!���������

<��)�����������

���� !" ���#���$%�&���143 Sparks Ave, Pelham, NY 10803-1837

:/= #%'2>7424&&�

Photonics Spectra July 2012

DPSS Lasers

Figure 4. Fine-grain alumina ceramic marked with a 532-nm Explorer laser system. A raster scanprocess created a 2-D data-matrix mark in whicheach marked pixel comprised a group of closelyspaced horizontal lines.

712_Feat_SpectraPhysics_Layout 1 6/25/12 3:41 PM Page 54

Beam Profiling Helps Make Medical Devices Better

BY JOHN MCCAULEY, OPHIR-SPIRICON

Applying beam profiling data isn’tas difficult as new users mightthink. But the best answers often

come from those who have applied beamprofiling practices in their own day-to-dayoperations. So, to help me answer thesequestions and address the stigmas relatedto the applications of beam profiling, Itraveled to beautiful Lake Geneva, Wis.,to see the engineers at Medicoil, a divisionof R&L Spring Co., a supplier of precisionsprings and wire forms to a wide range ofOEMs. Medicoil is a highly specializedmanufacturer of microprecision coiled and

formed wire products for the medical device industry.

On a typical day, Medicoil manufactur-ing engineer Ben Zimmerman ensures thatproduction is running smoothly. He takesthe lead on any new projects that comethrough the door, working with customersthroughout a product’s life cycle, fromR&D to production, to make sure it ismanufactured correctly. Lead productiontechnician Joel Bryant works on the floorwith R&D and production laser opera-tions, and with the maintenance of thelasers that they use.

Historically, Medicoil has been in-volved in manufacturing springs, coils andwindings, primarily for the medical devicecommunity. As time has gone on, the com-pany has gotten more involved with pro-viding assembled medical components. Its early use of lasers included glove boxspot-welding laser systems, which are sin-gle-pulse Nd:YAG lasers that use conven-tional optics and are housed in a small single-user workstation.

Today, Medicoil employs glove box andcomputer numerical control welding ma-chines. Its laser processes include the useof pulsed Nd:YAG lasers for micro spotwelding; however, cutting, drilling andother laser processes are in the near future.In addition, the company eventually willdesign and apply its own automated work-stations for its laser processes. Dependingon the process specification, each part willbe run through a setup and validation pro-cedure to ensure that all settings andranges are documented and controlled.

Medicoil also is working toward Inter-national Organization for Standardization(ISO) and American Welding Society(AWS) standards compliance. These standards are not currently required, butBryant and Zimmerman both realize thatas laser processing grows as a niche, themedical community will be faced with ad-ditional compliance standards from theFood and Drug Administration and ISO.“We took the step forward [implementinga laser validation program] before the cus-tomers were requiring it, as we want toknow where our processes are,” Zimmer-man said.

Medicoil has been conducting laserpower measurements for some time now –but Bryant said the company had not beenusing power meters to their full potential.“We did a check every morning, wrotedown what the power was, and that wasabout it,” he said. “We didn’t really moni-tor that because we didn’t know what to do with it.”

Eventually realizing that these lasershad far greater potential than their currentusage, they decided to educate themselves

55Photonics Spectra July 2012

The amount of time and energy needed to invest in the setup and useof an untried, but useful, piece of equipment can be daunting. But oncesome of the basics are explained, the initial effort seems far morepalatable. Here is a look at how one company implemented beam profiling to improve its manufacturing processes.

A camera-based beam-profiling system, a thermopile energy sensor and a photodiode sensor for capturing temporal pulse shapes. Images courtesy of The Ophir Photonics Group and Medicoil.

Beam Profiling Medicoil Feat_Layout 1 6/26/12 10:58 AM Page 55

on other laser manufacturing applicationsand on how best to develop measurementpractices and processes to help in meetingforthcoming industry standards.

Hands-on measurement Representatives from Medicoil attended

one of a series of laser beam processingcourses conducted by Simon Engel, presi-dent of HDE Technologies Inc. Engel is an independent consultant who conductscourses on laser beam diagnostics as wellas laser systems and process validation,among other topics.

“That class was a huge eye-opener,”Bryant said. “Before, we just plinkedalong with our little welders and ourpower meters, and we thought everythingwas good. Then we went to Simon Engel’sclass on beam diagnostics and beam pro-filing and realized that there is so muchmore out there, not only in terms of whatlasers can do, but also what we should bechecking on the lasers.

“A simple power check is a small frac-

tion of what you need to be looking atwith your laser beam to validate yourprocess and your equipment. We cameback from that class armed with a lot ofknowledge but also afraid, thinking, ‘Wedon’t do any of that! We had better start!’That’s what broke us into laser manufac-turing on a larger scale.”

Working closely with production,Bryant was now armed with knowledgeabout how to set up the laser and monitorits current process and performance. Zim-merman took the knowledge and applied it as someone working more closely withcustomers, ensuring that the lasers wouldbe doing exactly what the company saidthey would be doing – and providingproof.

Learning on the flyZimmerman and Bryant still needed to

discuss which laser measurement productscould best help them achieve these aggres-sive new goals. An on-site demonstrationof different beam profiling systems helped

them to determine the best solution fortheir laser processes and workstations.They then acquired a spatial beam profilerand a temporal pulse measurement system,which they use in conjunction with a laserpower and energy measurement system.

It turns out that, as soon as they pur-chased the equipment, a door opened forthem when a client asked for laser valida-tion – what a happy coincidence that theyhad been working on their laser validationprogram; otherwise, they would havemissed that opportunity.

Laser end users must understand the im-portance of gathering, documenting andanalyzing all obtainable information abouttheir laser systems. During discussionsand on-site demonstrations, it is some-times difficult to help potential customersmake the connection. Sometimes they say,“That sure is a pretty picture of my beam.Now what am I supposed to do with this?”or “That looks like it’s pretty difficult andcumbersome to use. I’m not sure I want to get into any science experiments,” or“Aren’t those beam profilers expensive?”

The laser jocks at Medicoil have madethat connection. “You can take the infor-mation that you’re getting off these [lasermeasurement] products,” Zimmermansaid, “and you can establish a validatedprocess so that every time you’re going torun a certain part, or every time you needto do a new setup, or every time you get a new machine, you’ll be confident inknowing that the machine or process isrunning at the appropriate parameters.Every time you run or use the laser,you’re sure that it’s set up the exact same way.”

“Now some places it might not be asstringent as in the medical device field, butfor us, it is definitely a huge priority. Themore proactive you are, the better. Takethis data, and set things up so that everytime you can say that process is validated.That covers your company so your cus-tomers know, ‘We are here. We know thatwe are validated. We can prove that ourprocess is the same every single time.’ ”

Ease of useZimmerman explained the ease of use

of a beam profiling system: “At first itmay seem big, a lot of things going on. Itmay seem out of this world to be measur-ing laser beams. But, really, when it comesdown to it, once you take the steps, it’s actually pretty easy.”

They plan to apply their relatively newknowledge and laser measurement prod-ucts to their laser validation program.

56 Photonics Spectra July 2012

Beam Profiling

Analyzing a laser beamBeam profiling involves using a device such as a camera or scanning slit to image all or part of a laser beam, then analyzing the image using specialized software. The data obtained from a beam profile can be used in several ways.

A laser user adjusts the Z height of the laser to image the focused spot.

Beam Profiling Medicoil Feat_Layout 1 6/26/12 10:58 AM Page 56

“We’ve been very happy with it,” he said.“We just started doing our first processvalidation, and we’re excited to actuallyuse it for its intended purpose. This will bea major stepping-stone for our company,and hopefully it really gets us out there,showing that we are compliant.”

It seems that beam profilers are stillviewed by a lot of industrial laser users ashigh-level scientific equipment, more lux-uries than necessities, difficult to set upand operate and – worse – expensive.These arguments may have been valid inthe past, but today, because of advances inlaser measurement technology and be-

cause of input from customers, providersof laser measurement solutions can confi-dently say that there are now products thatare simple, easy to set up and use, andnowhere near as expensive as expected.

Anyone who works with lasers knowsthat no two lasers are created equal. Evenwith today’s high-quality industrial lasers,simply plugging in a duplicate set ofprocess parameters – even into a duplicatelaser system in a duplicate workstationfrom the same laser manufacturer or sys-tem integrator – does not mean that thosetwo lasers are going to perform the exactsame way every time. The only way to

know for sure that your lasers are per-forming consistently from system to system and from day to day is through acomprehensive laser systems and processvalidation program using the latest laserbeam measurement solutions.

Meet the authorJohn McCauley is Midwest regional sales manager at The Ophir Photonics Group in Indi-anapolis; email: john.mccauley@us.ophiropt.com. For information about the laser systemand process validation classes discussed in thisarticle, contact Simon Engel of HDE Technolo-gies Inc.; email: simonlaser@yahoo.com.

57Photonics Spectra July 2012

Beam Profiling

Beam profiling software shows a focused laser beam (left), an out-of-focus beam (center), and a focused beam, the energy in that pulse, and its temporal shape (right).

Beam Profiling Medicoil Feat_Layout 1 6/26/12 10:58 AM Page 57

Electronics Augments ModernProcess Control Spectroscopy

BY GERT NOLL, TEC5USA INC., AND MATHIAS HOLZAPFEL, TEC5 AG

When spectrometers were touchyinstruments confined to labora-tories, the features that mat-

tered were the spectral range and resolu-tion that the device could obtain withoutsacrificing sensitivity. Timing did not mat-ter because the single-element detectorsshowed momentary values only. The over-all readout times were measured in min-utes rather than seconds – or even less.The grating or prism moved slowly toscan a wavelength range, and users hopedthe spectrum did not change drasticallyover time so that the final signal repre-sented the same status as the initial values.

With the advent of detector arrays, the whole picture changed: There was no worry about slow-moving dispersiveelements anymore; a spectrum could becaptured in milliseconds.

As long as the spectrometer readout isnot electronically linked to any process,the timing is in the hands of the operator,to hit the key when the time is ripe. Sub-second exposure times opened the door to a whole new world: the spectral moni-toring of fast processes. Faster measure-ment allows acquisition of more samples,so it provides more accurate in-line infor-mation. Processes such as film coatingscould be controlled with much greater precision, showing how important timeand timing are.

Part 1: Detector-Array Electronics

Modern process-control demandsThe most important feature of a spec-

trometer is that it covers the spectral region of interest. Often, the demand for

Photonics Spectra July 201258

Good wavelength accuracy andhigh sensitivity are key opticalfeatures of a spectrometer system, although resolution is a matter of mechanical design.However, in process control, thedetector array and the relatedreadout electronics are oftenmore crucial for a successful application, and a large signal-to-noise ratio and a high dynamic range are sought-afterfeatures. Moreover, monitoringfast processes, such as a pulsedsolar simulator, requires operating electronics with precise timing.

Figure 1. Time distribution of a pulsed solar simulator. Courtesy of Tec5USA Inc.

Tech 5 Spectroscopy Feat_Layout 1 6/25/12 3:39 PM Page 58

resolution is mixed up with the demandfor accuracy. For example, if measuringthe slope of a transmission filter deter-mines the cutoff wavelength, there is littleto discriminate between two wavelengths– but it is important that the slope is al-ways measured at exactly the same wave-length. Resolution often must be sacrificedover sensitivity, because a fast measure-ment can be accurate with respect to intensity only if enough light is hitting the detector, and the shorter measurementtimes allow less light to hit the detector. A larger bandwidth per pixel, however,leads to more light per pixel. Thus, thesignal measured by each pixel is higher,but the consequence is lower spectral reso-lution. Therefore, a high sensitivity is thefirst demand for fast measurements.

Without the millisecond readout of anarray, no fast processes can be observed orcontrolled. Therefore, the second demandis to measure quickly, which almost seemsto be a trivial statement.

To achieve a large dynamic range – the capability to measure small and largesignals – the detector needs a high-wellcapacity, and the electronics and the ana-log-to-digital converter that match it. Thecombination of detector and electronicsalso needs a good readout quality with low noise. At 16-bit conversion, a readoutnoise of 1.5 counts rms results in a dy-namic range of more than 40,000 (highestdivided by lowest signal measurable).

Some spectrometer systems give the impression that although spectrometerscan be read out in milliseconds, exact timing – at what precise time a spectrome-ter is read – does not really matter. Solarsimulator monitoring shows that timingdoes matter and that it is crucial to thequality of a measurement.

Background: Timing, accuracyTo measure light intensity accurately,

the time period over which the light is collected must be precisely controlled. The readout time directly influences theamount of measured signal: If the readouttime is 1 percent too long, then 1 percenttoo much light is detected.

One timing aspect in a process environ-ment is the reaction time from synchro-nization to external events. Typically,these events send a trigger signal, and the measurement system must react on this event within a specified time.

This reaction time depends only on the electronics and its implemented work

mode. In nontriggered environments, theelectronics operates the detector array in a free-running mode, where the sensoris read out in time intervals based on theintegration time. To view a spectrum, anoperator can send a software request. Ifthe electronics is reading out the sensor at the time of the request, then it finishesthe data acquisition before it records thenext spectrum.

In a standard triggered mode, the soft-ware request is replaced by the triggerevent. As with the free-running mode, itcould take up to one integration period

until the spectrum of the sample requestedby the trigger event can be recorded. Thedelay is that long if the detector arrayelectronics is busy with a readout cycle.Such a delay may be several milliseconds,which is not acceptable in many situa-tions. For example, a sample on a con-veyor belt might have passed already, orthe state of a technical process may havealtered within this delay time. Further-more, a jitter would appear if the sampleswere not passing by regularly or if themonitored event had no exact time refer-ence to the recording period. In such a

59Photonics Spectra July 2012

Figure 2. Comparison of spectrometer electronics quality: same event recorded with the same detector arrayand parameters but different electronics. Courtesy of Tec5USA Inc.

Figure 3. Comparison of the spectral outputs of a solar simulator based on flashlamps and the standardizedemission spectrum of the sun as found on Earth. Courtesy of Tec5USA Inc.

Tech 5 Spectroscopy Feat_Layout 1 6/25/12 3:39 PM Page 59

case, a different detector-array work modeis required. Rather than wait for the nextintegration cycle, the electronics interruptsthe acquisition immediately after receivingthe trigger signal and starts a new scan.This minimizes the delay to a few microseconds.

Another issue can be the readout rate.On the millisecond timescale, the spectralacquisition of silicon detector arrays is not a simultaneous process. Often, the pixels of a detector array are read out oneafter the other so that each pixel representsa slightly different time period. The lastpixel contains information from a com-

plete scan time – a couple of milliseconds– later. This effect can be minimized onlyby a high readout frequency (clock rate) of the detector chip, a generally importantdesign goal.

A 1-MHz clock frequency is about thehighest frequency suitable for high accu-racy, and the overall readout time is about1 μs (treadout = Npixel/fclk). For silicon PDAsand CCDs, the readout time normally rep-resents the shortest exposure or integrationtime. To achieve an accuracy of 0.1 per-cent (about 10 bits), the timing accuracymust be 1 ms/1000, or about 1 μs. How-ever, to reach 16-bit accuracy, the timing

must be precise to 15 ns. Therefore, agood analog-to-digital converter must beaccompanied by an exact timer for the in-tegration time control. The downside to ahigher frequency is a lower quality of thesignal readout. The engineering goal is tofind the most suitable compromise.

Part 2: Solar Simulator Monitoring

Pulsed eventsA typical modern application is the

monitoring of solar simulators, oftencalled “flashers.” The flashers emit milli-second light pulses that spectrally mimicthe light generated by the sun. The simu-lated sun helps to characterize solar cellsin a neutral, reproducible way. This appli-cation is very demanding because of therequired precise triggering and fast dataacquisition. The emitted spectra vary notonly from flash to flash, but also over the duration of each flash. Thus, a fastreadout is essential: More spectra can betaken across the time axis of a flash if theacquisition times are short, representing a high time resolution.

Figure 1 (page 58) shows a typical time distribution of a solar simulatorpulse. The efficiency of solar cells ormodules is measured during the equilib-rium phase of this light pulse, because thatis when the emitted light spectrum is sta-ble. During the rising and falling edge, theflash spectrum is rapidly changing. Thus,it is important to measure the spectrum ata precise time after the flash has started.

Measuring at the right time on the equilibrium phase needs a precise triggerevent. To achieve independency of the

60 Photonics Spectra July 2012

Process Monitoring

Figure 5. Flasher in a solar test handling system.Courtesy of ASYS Solar.

Figure 4. Detailed view of solar cell test station. Courtesy of ASYS Solar.

Figure 6. A system with spectrometer, trigger electronics and the (outside) detector surface to tap the flash for trigger-signal generation. Courtesy of Tec5USA Inc.

Tech 5 Spectroscopy Feat_Layout 1 6/25/12 3:39 PM Page 60

flasher electronics, it is best to use theflash itself. This requires the implementa-tion of a separate single-element photo-diode detector to detect the light.

Because the spectrometer is still sensi-tive during the idle phase, a signal fromambient light and dark current accumu-lates on the detector over time. This signalwould affect the flash spectrum, so thespectrometer detector is first cleaned by areadout of the array without recording thespectrum. This cleaning requires a specialdetector-array work mode. (Modern elec-tronics allows implementation of newwork modes by uploading firmware.)

Timing of wide-range systemsRecording the full flash spectrum over

a wide spectral range requires multiplespectrometer units, each equipped with adifferent sensor technology for the variousspectral ranges. Silicon-based detectorchips are sensitive from the ultraviolet upto about 1 μm, while InGaAs detectors detect light above 1 μm. Combining thetwo detectors is a challenging applicationthat requires exact timing information forboth sensor arrays involved.

Unfortunately, both detector types have

different readout principles: Although aSi-based detector is sensitive all the time,an InGaAs detector is sensitive only dur-ing the exposure phase. The latter is notsensitive during the readout phase, whichlasts about 1 ms, if readout frequency ishigh. This supports the request for a highreadout frequency.

If both sensors have to collect light overthe same equilibrium-phase period, theyboth must be triggered at different timepositions. To compensate for the “blind”phase, the near-IR spectrometer unit mustbe triggered about 1 ms, or exactly thereadout time of the used chip, which isearlier than the Si detector should be trig-gered. Also, the cleaning timing differswith various sensor technologies.

To prepare the flash emission determi-nation described above, a so-called “burst”mode acquires spectra across the completeflash time period as quickly as possible. A burst is a defined number of spectrarecorded one after the other without anyadditional delay. These spectra provide information of the various time zones ofthe flash: Plotting a single wavelengthover time reveals the envelope of the flash intensity over the time axis.

A good signal-to-noise ratio is requiredfor a high-accuracy measurement. Acquir-ing as many spectra as possible during the whole equilibrium phase is highly recommended so that the signal qualitycan be improved by averaging. However,the acquisition window should exclude therising or falling edge of the pulse to avoida deformation of the spectral information.

To monitor fast processes, detector arrays must be operated at fast readoutrates; short integration times require timing accuracy in the nanosecond range.A flasher monitor needs a delay function-ality to confine the spectral measurementto the equilibrium phase only, and timingmust be carefully controlled to account for different cleaning and delay times for the sensor technologies involved. Vari-ous work modes must be implemented tomatch the performance of the spectrometersystem precisely to the multifold task.

Meet the authorDr. Gert Noll is general manager at Tec5USAInc. in Plainview, N.Y.; email: gert.noll@tec5usa.com; Mathias Holzapfel is productmanager at TEC5 AG in Oberursel, Germany;email: m.holzapfel@tec5.com.

61

Sales (877) 396-7846 FAX (585) 265-1033 www.optimaxsi.com/Aspheres

Visit us at SPIE Optics + Photonics, Booth #535

Photonics Spectra July 2012

Process Monitoring

Tech 5 Spectroscopy Feat_Layout 1 6/25/12 3:39 PM Page 61

Deal with Bigger Deviations

BY HANK HOGANCONTRIBUTING EDITOR

A spheres are increasingly used for a variety of applications becausethey offer more performance than

spherical lenses. Also, the asphere boomhas been fueled by the availability of pre-cision computer-controlled machining andsurfacing tools.

“More and more vendors have the capa-bility to manufacture aspheres than theyhad in the past,” said John F. Filhaber, director of special programs at the Middle-field, Conn.-based Zygo Corp. The com-pany supplies optical metrology instru-ments, precision optics, and associateddesign and manufacturing services.

Once upon a time, surfaces rarely de-parted from the spherical, and if they did,it was by a few hundred microns at most.Today, 800-μm deviations are becomingcommon – and even larger numbers loom.

One measurement option is to use someversion of a laser interferometer, with awavefront from an asphere interferingwith that of a reference. The resultingfringes illuminate how the actual surfacediffers from the reference. If the differenceis large, the density of fringes will be highand the fringes perhaps unresolvable.

A Fizeau interferometer overcomes thisby scanning the reference wavefront alongthe surface and collecting data only wherethe local fringe density is low. Conse-quently, such instruments are accurate andquick, and they can measure deviations>800 μm with a high data density. For instance, Zygo’s laser-based Verifire Asphere typically requires only minutes to capture and process the data from up to 700,000 points with a surface measure-

ment repeatability of less than 10 nm, Filhaber said.

Another asphere metrology technique isprofilometry, in which a probe traces outthe surface profile. Advantages include theability to handle a variety of slopes andshapes. Disadvantages involve speed anddata density, which are related becausemore data can be extracted at the cost of alonger scan time. Another drawback is thatthe Z-resolution will not be as fine as itwould be with an interferometer.

Shape and resolutionFor its part, optics manufacturer Opti-

max Systems Inc. of Ontario, N.Y., usesboth interferometry- and profilometry-based methods, said engineer Brandon

Light. The choice between the two comesdown to asphere shape and the requiredresolution, as well as to the cost and timeneeded to do the test.

The latter can involve much more thanwhat the test itself requires. For instance,computer-generated holograms can enableinterferometry of very complex aspheres,with deviations in the hundreds of mi-crons. In this case, the reference wavefrontis generated from a carefully constructedhologram. The technique is part-specific,and the hologram can take months to fab-ricate. It also can cost tens of thousands of dollars.

Interferometry in general has benefitedfrom technological advances, Light said.“One of the big revolutions was the rise

Photonics Spectra July 201262

New tools and the integration of measurement capabilities into design software are helping to solve problems – and scientists in academic and government laboratories are researching tomorrow’s solutions.

Data from asphere metrology systems show 3-D information (top) on form deviation from design parametersand a base radius. Below are 2-D slices, such as might be provided by a stylus moving across the surface.Courtesy of Zygo.

Aspheres

712AsphericOptics_Layout 1 6/25/12 4:14 PM Page 62

in a much more densely pitched focalplane array.”

For example, he noted that 640 � 480arrays have been replaced by ones measur-ing 1000 pixels on a side, leading to amore than threefold pixel-count increase.This greater density enables finer fringesto be resolved, increasing the amount ofdeviation from the spherical that can behandled. Further advances in this areacould provide still more improvement.

There are other innovations that couldhave a significant impact. In particular, de-sign software is beginning to incorporateprovisions for metrology capabilities. This will constrain what can be designedto what can be built and measured, Light said.

QED Technologies International Inc. ofRochester, N.Y., extends the capabilities ofinterferometers through a divide-and-con-quer approach. Its instruments segment anasphere into subapertures. These cover theentire surface, with enough overlap so thaterrors resulting from the interferometer,alignment or other sources can be cor-rected out or, at least, quantified.

In theory, any shape can be measuredby dividing the surface into small enoughsubapertures. Measurement time consider-ations limit what can be done in practicalterms, as does the computing power re-quired to align the various subapertures together.

In its original stitching interferometer,QED Technologies used a spherical wave-front for its source, which has implicationsfor the size of subapertures. They must besmall enough to keep the fringe densitymanageable. However, the latest iterationof the technology changed that andthereby increased the instrument’s aspheremeasurement capability, said Andrew Kulawiec, company president.

“We introduced what we called theVariable Optical Null device, or VON,which is basically an optical null lens thatis configurable to nearly match the shapeof each subaperture in the asphere,” hesaid.

The company recently announced itsown interferometer, which is optimized forstitching. This enables measurements withhigher fringe densities and greater con-trast.

QED Technologies also is working toget metrology and other constraints intodesign software. This is being donethrough the use of polynomials that betterdescribe an asphere’s shape. Investigations

63Photonics Spectra July 2012

Top, a stitching interferometer can measure a steeply curved asphere surface precisely by segmenting it into subapertures. Courtesy of Optimax Systems.

Bottom, using a variable optical null enhances interferometric metrology by allowing a reference wavefront to more closely match a surface. Courtesy of QED Technologies.

712AsphericOptics_Layout 1 6/25/12 4:14 PM Page 63

have shown that this approach can lead tobetter overall system performance andlooser assembly tolerances, Kulawiec said.

An example of an advance in profilom-etry comes courtesy of OptiPro SystemsLLC of Ontario, N.Y. Originally devel-oped to meet a US Navy requirement tomeasure very steep surfaces, the com-pany’s UltraSurf is a noncontact profil-ometer with five axes of motion, whichallow it to make 3-D measurements bytracing over an asphere. This is done whilemaintaining the probe perpendicular to thesurface.

That last item is important because itenables an optical probe using low-coher-ence interferometry to measure near andfar sides as well as thickness of a compo-nent simultaneously. The material must be

transparent to the wavelength used and ofuniform thickness. Also, keeping the probeat right angles to the surface means thatalmost any shape can be measured.

This optically based profilometer has anadvantage over interferometers. It workswith a bright probe that sits near theasphere and doesn’t illuminate the entiresurface at once.

“You can measure parts in a groundstate or a polished state,” said EdwardFess, an OptiPro senior research engineer.“It’s a focused spot, so there’s enoughlight intensity so that it can get reflectionsback even from a ground surface.”

The scan of a surface is done at 100-nmaccuracy, which is close to that from aninterferometer. Scans take from 30 s to 30min, depending upon the density of col-

lected data points. Measurements must bespaced closely enough to capture periodicsurface fluctuations that arise from grind-ing and polishing, which generally meanspoints spaced from 100 μm to as much as5 mm apart, Fess said.

Looking aheadAs for the future of asphere metrology,

one place to keep an eye on is the Univer-sity of Arizona in Tucson. There, a groupled by James H. Burge, a professor of optical sciences and astronomy, pushesmeasurement technology to the limit. Ithas to so as to build the big mirrors andother optics that power advanced tele-scopes.

Burge has worked with interferometersand profilometers, often pioneering tech-

64 Photonics Spectra July 2012

Asphere Metrology

Method Cost of Test Setup1 Setup Time2 Test Time3 Tolerance Limit Maximum Departure Comments

Surface Contact Measurement

Coordinate Measuring Low Minutes ~10 Min �5 µm mm No required symmetry;Machine requires datum and fixturing

Profilometry Low Minutes ~5 Min �0.5 µm �25 mm Most common method;provides only 2-D data

Surface Testing in Reflection

Spherical Wavefronts Low Minutes ~10 Min 0.1 Fringes ≤10 µm Zernike subtraction;fringe density limited

Computer-Generated High Months ~20 Min 0.25 Fringes mm No required symmetry;Hologram part-specific

Spherical Null Reflection High Weeks ~10 Min 0.1 Fringes 100 µm Part-specific

Parabola/Ellipse Average Hours ~30 Min 0.1 Fringes mm �1 ≤ k �0

Subaperture Stitching Average Minutes ~30 Min 0.1 Fringes �650 µm Absolute test

Annular Ring Stitching Average Minutes ~15 Min 0.1 Fringes �800 µm Discontinuous at sagittal zero curvature

Lens Testing in Transmission

Transmitted Average Hours ~10 Min 0.1 Fringes �50 µm Must be well-behavedWavefront Error aspheric lens

Computer-Generated High Months ~20 Min 0.25 Fringes mm No required symmetry;Hologram part-specific

Spherical Null Transmitted High Weeks ~10 Min 0.1 Fringes ~100 µm Part-specificWavefront Error

1Relative cost of tooling and labor for each test2Includes time to obtain needed components and alignment of system3Includes time for alignment of unit under test, data collection and analysis

Comparing Asphere Metrology Methods

712AsphericOptics_Layout 1 6/25/12 4:14 PM Page 64

The method works by modulating whatis on the screen, such as by shifting shapesaround or altering their color. The testmust be carefully designed and the detec-tor properly calibrated. The payoff is aflexible approach that can be used to testan optical component, achieving the sameaccuracy as computer-generated holograminterferometry at a cost of a few thousanddollars. The technique can even measurethe performance of an entire optical sys-tem by placing the screen at one end andthe detector at the other.

Finally, at the National Institute forStandards and Technology in Gaithers-burg, Md., physicist Ulf Griesmann andothers are working on the metrology ofprecision surfaces, such as those found inhigh-performance optics, disk drives andartificial joints. Recently, they have beendelving into holograms for interferometricasphere metrology to understand what thelimitations are. They also want to developmethods that will improve hologram man-ufacturing and complex surface metrology.One challenge is micron or smaller place-ment errors across distances of tens ofmillimeters.

Successful technology development willbe transferred to industry, and aspheremetrology will benefit. But Griesmanndoubts that whatever is devised will leadto a single measurement technique.

“In metrology,” he said, “there’s never aone-size-fits-all solution.”

hank.hogan@photonics.com

Photonics Spectra July 2012

Asphere Metrology

Five axes of motion allow this profilometer to measure almost any asphere shape. Courtesy ofOptiPro.

The XCaliber interferometer enables NIST researchers to do surface metrology of precision optics, including aspheres. Courtesy of NIST.

niques. One example is the swing arm op-tical coordinate measuring machine, a pro-filometer with a distance-measuring inter-ferometric probe.

The group’s latest method involvesscreens, such as those found in large mon-itors or televisions. These form whatBurge calls a software configurable opticaltest system, or SCOTS, which can be usedfor metrology of various surfaces.

“To measure a mirror, all you do is takea computer screen and put images on thatscreen. You look at that screen in reflec-tion off the mirror. Basically, the distor-tions that you see have the information onthe mirror surface irregularity,” Burgesaid.

712AsphericOptics_Layout 1 6/25/12 4:14 PM Page 65

66 Photonics Spectra July 2012

Optics & Optics Fabrication

New 80 � 80 FPA for High-Speed MWIR DetectionNew Infrared Technologies brings to the market the new uncooled MWIR FPA of 80 � 80 pixels: high-speed MWIR (1 to 5 µm) data acquisition at thethrilling speed of 2500 frames per second (at 80 � 80, full frame, snapshotmode) in real uncooled operation. The new FPA has the ROIC (readout integrated circuit) monolithically integrated, digital interface for easier integration and individual pixel dark current correction. A low-res version (32 � 32) is also available (10,000 fps at 32 � 32). The new FPAs from New Infrared Technologies: uncooled MWIR imaging faster and larger than ever!

+34 91 632 43 63sales@niteurope.comwww.niteurope.com

Custom Precision OpticsDiMaxx Technologies specializes in custom precision optics such as windows,spherical lenses, prisms, flow tubes and polished metal surfaces. We fabricatelaser-quality optics for the medical, scientific, military, biotechnology andother markets. Typical specifications include fused silica and BK-7 surfaceroughness of <3 Å, with surface quality of 10-5 or better. Optics from 3 to 300 mm. CNC experts for high-accuracy machined glass components.

(530) 888-1942info@dimaxxtech.comwww.DiMaxxTech.com

Measuring Lens Centering, Air Spacing

and Center Thickness with One InstrumentOptiCentric® 3D is a two-in-one solution for the detailed investigation of assembled objective lenses. It combines the OptiCentric® centering errormeasurement technology with the low-coherence interferometer OptiSurf®,measuring the air spacing and center thickness within the optical system. This cross-interaction procedure allows aligning the lens system fast and precise. This provides a significant increase of measurement accuracy and detailed quality information:

• Centering errors of <0.1 µm• Air spacing and thickness of <1 µm

+49 4103 180 060info@trioptics.comwww.trioptics.com

Full Power Across the SpectrumOptical filters from Chroma provide precise color separation, signal purity and optical quality. Whether your application is fluorescence microscopy, flow cytometry, confocal or multiphoton microscopy, or other applications requiring precision optics, our filters provide optimum results. BP/LP/SP *Multiband * Notch * Dichroic Mirrors * Polychroic Mirrors * UV/VIS/NIR * AR Coatings * Hot/Cold Mirrors * ND/AG/AL Mirrors * Laser Grade and more,engineered and manufactured by a team of employee-owners committed tobringing you the finest optical filters, filter sets and optics solutions.

(800) 824-7662sales@chroma.comwww.chroma.com

New Product! 2-µm IsolatorsNew 2-µm isolators from Innovation Photonics operate from 1.9 to 2.5 µm and offer features including:

• 4 mm Aperture• Tunable Wavelength• Transmittance: >90%• Isolation: >30 dB

A catalog is available upon request.

(973) 857-8380info@innpho.comwww.innpho.com

712_Spotlight_Layout 1 6/25/12 3:42 PM Page 66

67Photonics Spectra July 2012

Optics & Optics Fabrication

Very Long Wavelength Infrared (VLWIR) FiltersDSI’s new very long wavelength infrared (VLWIR) filters include narrow and wide bandpass filters (NBP and WBP), long- and shortwave pass filters (LWP and SWP), and antireflection (AR) coatings. They provide hightransmittance over the 12µm to beyond the 22µm-wavelength region. They readily pass all standard environmental tests and can be repeatedly cycled between ambient and cryogenic temperatures without degradation.Commonly used VLWIR substrates include germanium (Ge), zinc selenide(ZnSe), silicon (Si) and indium antimonide (InSb). Ideal for remote sensing,chemical analysis, astrophysics/astronomy, and horizon sensors.

(707) 573-6700solutions@depsci.com

www.depsci.com

Automatic Centering Machine with RobotModel SPCM-M1-AT50 from Mildex centers and bevels lenses or plano workpieces in a fully automatic cycle, including loading and unloading of the workpieces by robot. The machine has two integrated lens holding pallets.Depending upon lens size, up to 600 lenses can be loaded for automatic processing. Once processing parameters are set by the operator, the machinecan run uninterrupted for four to eight hours. The small footprint saves factory floor space.

(585) 473-6540info@mildex.comwww.mildex.com

Complete Turnkey SolutionsPG&O supplies complete in-house turnkey optics solutions, including precision and commercial components, thin-film coatings, fabrication and a large, readily available inventory of glass. Products include windows,mirrors, prisms and assembled optics, from square, rectangular and circularparts to complex shapes and precision optical prisms. Ideal for military/defense, avionics displays, medical, life sciences, imaging, digital cinema,solar, industrial and astronomy applications.

(714) 540-0126info@pgo.comwww.pgo.com

New sCMOS CameraThe new Zyla 5.5-megapixel scientific CMOS (sCMOS) camera is ideal for research and OEM usage. Zyla sCMOS offers a 100-fps rate, rolling and snapshot (global) shutter modes, and ultralow noise performance in a light, compact and cost-effective design. Zyla achieves down to 1.2-electron rms read noise and can read out the 5.5-megapixel sensor at a sustained 100 fps through a “10-tap” Camera Link interface. A highly cost-effective “3-tap” version is also available, offering up to 30 fps.

(800) 296-1579info@andor.comandor.com/zyla

Precision Polymer OpticsG-S Plastic Optics manufactures precision polymer optics for imaging, scan-ning, detection and illumination applications. In addition to an extensive cata-log offering of plastic optics, the company has in-house capability to providecustom-designed diamond-turned and injection-molded prototypes, produc-tion injection molding of optics, thin-film and reflective coatings, and inte-grated optical solutions for the military, medical, commercial and consumermarkets. (585) 295-0200

info@gsoptics.comwww.gsoptics.com

712_Spotlight_Layout 1 6/25/12 3:42 PM Page 67

68 Photonics Spectra July 2012

Optics & Optics Fabrication

Custom OpticsSwift Glass specializes in providing short lead times for high-volume manufacturing requiring optical tolerances and multiple diameter variances.Capabilities include: double-sided lapping and polishing; ceramic and crystallapping and polishing; precision parallel components; scratch-dig to 20-10;machining center for close dimensions; surface coating availability; opticaledge polishing; color filters; ¼-in. diameter to 36 in. square.

(607) 733-7166quality@swiftglass.com

www.swiftglass.com

AccuFiz Compact Laser InterferometerThe compact AccuFiz® Fizeau laser interferometer offers an unmatched combination of performance, quality and value for highly accurate shape and transmitted wavefront quality measurements. The AccuFiz provides unparalleled accuracy at midspatial frequencies, letting you measure polishing artifacts that other interferometers simply miss.

Standard features include a touch-screen remote, Smart Zoom™ for repeatable lateral resolution at all zoom settings, and user-friendly 4Sightanalysis software. Optional Dynamic Interferometry® capability lets you measure despite vibration, without an air table.

(800) 261-6640info@4dtechnology.comwww.4dtechnology.com

High-Performance CCD LensesWestech offers a full line of lenses for linear and area arrays. Focal lengthsrange from 1.8 to 150 mm. Apertures start at f/0.8. Lenses are 4, 6, 8 or 9+ element construction. Lens design and engineering services are alwaysavailable, and Westech offers total quality management. Westech specializesin producing high-volume precision optics. Don’t pay catalog prices for OEM optics.

(585) 377-2490jcarlino@westechoptical.com

www.westechoptical.com

Top-Hat Laser Beam ShaperOsela Inc.’s Top-Hat Beam Shaper converts a Gaussian laser beam to a top profile with high uniformity and high efficiency within a compact and flexible housing with dimensions as small as 19 mm in diameter by 30 mm in length. Its all-glass design is achromatic and offers smooth, slow intensityvariations with no high-frequency noise. (514) 426-2262

info@oselainc.comwww.oselainc.com

Nanopositioning Stages, Motors and Sensors, and Hexapods PI’s precision positioners, piezo actuators, flexure guided stages and capacitive sensors combine subnanometer stability with submillisecond responsiveness.

• 1- to 6-axis stages with many digital control options • Ultrasonic motors for high-speed automation • Piezo stepping linear motors for high-force, high-precision applications • Hexapods for optics alignment • Hybrid linear translation stages for long travel and nanometer precision

(508) 832-3456info@pi-usa.uswww.pi-usa.us

712_Spotlight_Layout 1 6/25/12 3:42 PM Page 68

APPLYNOW

Call for Entries

PRESENTED BY SPIE & PHOTONICS MEDIA

l flaC

S MEDIA SPIE & PHOTONICY PRESENTED B

ards.orgwPrismAseirtnr Eol f

pmociehT

YAAPPLYAPPLLLYLYLYOWNOWOWN

gnocernoititeplnaoitnaretn

YYWW

g nizign

onthopd ina

sadeielalhcnittucp

scione tfie lvorpmd i

leborpveols,stnevnocgene

dore pgde-gngnp

hguorhe t

,smlealniot

tahs ttcudg gn

PrismAwards.orgApply online by 14 September 201

onthop

PrismAwards.orgApply online by 14 September 201

.scion

2: Apply online by 14 September 201

712_PrismAwardsAd_Pg69_Layout 1 6/25/12 4:11 PM Page 69

70

Silicon Polarizing Beamsplitter Cubes �REO has introduced silicon polarizing beam-splitter cubes for the mid-infrared range. Theoptics offer 2- to 6-µm-bandwidth operation,transmission >95% and an extinction ratio>100,000:1. The devices are available in sizesfrom 1 to 75 mm. Typical laser damage thresh-old is in the 1.5-J/cm2 range for a 75-ns pulseat 2.05 µm. This is achieved through the use of ion-beam-sputtered coatings and assemblybased on proprietary Activated Covalent Bond-ing technology, which eliminates all organics or glues from the beam path, produces a strongbond and delivers low transmitted wavefrontdistortion. The cubes are durable and insensitiveto shock, vibration and high g forces. The opticsare used in cryogenic environments and in in-dustrial, military and space-borne applications.The polarizing beamsplitter cubes are used withoptical parametric oscillators and optical isola-tion for fiber and quantum cascade lasers.REOmarkd@reoinc.com

16-Megapixel Camera

PPT Vision has extended its M-Series embeddedvision family of cameras with a 16-megapixelmodel supported by an updated version of theproprietary Impact Software Suite. The GigE-compatible camera is designed for inspectionsthat require high-resolution, high-quality im-ages and a wide field of view, and it withstandsthe rigors of manufacturing settings. Applica-tions include flat panel LCD and printed circuitboard inspections, and printing processes. Features include Class 1 CCD sensors, indus-trial-grade construction and testing, good ther-mal management, low-noise performance andprecise alignment of a large sensor, with vari-ance of <0.1 mm. Version 10.4 of the ImpactSoftware Suite supports all M-Series embeddedvision systems. A simpler interface makes navi-gation easy, with faster, more efficient image-saving and image-filtering tools, and a new calibration mode is available for user-entered,point-to-point calibration.PPT Visionnancyk@pptvision.com

Miniature Spectrometer �B&W Tek Inc.’s Exemplar miniature spectrometer includes an em-bedded processor for onboard data processing, averaging, smooth-ing and automatic dark subtraction. USB 3.0 communication transfersdata at 900 spectra per second, and multichannel capabilities delivertrigger delay of 14 ns and gate jitter of �1 ns. Applications include high-speed binning and sorting,reaction kinetics and process monitoring. Supporting up to 16 simultaneous channels, the instrumentperforms multipoint sampling and laser-induced breakdown spectroscopy. End-user and OEM cus-tomers can use the onboard data processing and scalable, multichannel configurations to achieve simultaneous analysis at nanosecond accuracies. Features include temperature compensation, a2048-element detector and a 16-bit digitizer with a >2-MHz readout speed. The device is suitable for UV, VIS and NIR applications with spectral configurations from 200 to 1050 nm and resolutionsbetween 0.5 and 4 nm. Custom configurations are available.B&W Tek Inc.sales@bwtek.com

Hyperspectral Imager �Bodkin Design & Engineering LLC has launched the VNIR-90,a snapshot hyperspectral imager based on proprietary andpatented HyperPixel Array technology. The imager has an optical processor that captures the full hyperspectral datacube in each video frame instantly. The system can bemounted on moving platforms or used as a handheld devicefor capturing transient events or moving objects. Coveringthe spectral range from 500 to 910 nm, it produces a datacube of 55 � 44 spatial pixels � 90 spectral bins. Averagespectral resolution is 4.56 nm per bin. Interchangeable C-mount lenses enable variable fields of view. The system is supplied with a USB interface, a laptop PC, and loadedcapture software to produce environment-for-visualizing-images-compatible data cubes. Applications include foliage detection, characterization of skin lesions, detection of bullets in flight and development of cosmetics.Bodkin Design & Engineering LLCsales@bodkindesign.com

White LED Excelitas Technologies has announced anaddition to its ACULED family of chip-on-board LED packages. It combines corre-lated color temperature (CCT), a highcolor rendering index (CRI), a high R9value and the light output needed formedical applications including surgical,dental and examination lighting. Four

separately addressable LED chips provide tunable CCTs from 3500 to 5500 K. CRIs are greater than95, with R9 values above 90. R9 value indicates how well the light shows deep, saturated shades ofred, a critical color in surgical applications. The LED provides good heat transfer from the chips to the substrate and heat sink. It is designed with closely spaced chips, enabling improved color mixingand compact optics. The standard four-chip chip-on-board package (Model R3C6) is supplied withwarm-white, cool-white, red and cyan LED dice.Excelitas Technologiesmedia@excelitas.com

2-kW Fiber Laser �The JK2000FL 2-kW fiber laser revealed by JK Lasers offers good beam quality and high processing power and can be used with processing fibers with diameters from 100 to 300 µm for cutting and welding sheet metal. It can cut 15-mm-thick low-carbon steel (LCS), 6-mm aluminum alloysand 10-mm stainless steel (304SS), and can weld 8-mm LCSand 304SS. It delivers stable output power and a consistent focused spot size and beam profile over the power range. Pro-prietary detachable plug-in prealigned beam delivery fibers incorporate patented backreflection protection to shield thelaser from damage when processing highly reflective materials.Wall-plug efficiency is >25%. The >300,000-h mean time tofailure for the laser pump sources extends system lifetime. Featuresinclude software, fast modulation and pulse shaping. An optional time-shareunit simultaneously connects four separate workstations. JK Laserssales@jklasers.com

IDEASBRIGHT

Photonics Spectra July 2012

�

�

712BrightIdeaLeads_Layout 1 6/25/12 3:40 PM Page 70

Hyperspectral Retinal Imaging System

Targeting hyperspectral retinal imaging, Photonetc. has unveiled the IRIS system for noninvasivelocalization of biomolecules in the eye fundus.Based on a mydriatic retinal camera and a pro-prietary tunable laser source, the instrumentperforms high-definition imaging from 420 to1000 nm. It is a research tool for developingtreatments for diseases such as diabetic retinop -athy and age-related macular degeneration. Anautomatic spectral calibration setup guaranteesspectral reproducibility, while a photodiode pro-

vides temporal normalization of the light inten-sity. The instrument includes a CCD camera andan X-Y-Z manual positioning system. The illumi-nation is based on proprietary and patentedBragg grating filtering technology and enablesrapid and accurate wavelength selection from a supercontinuum source. The system providesnoninvasive localization of structures and bio-molecules in the retina using their specific spectral signatures. Photon etc.info@photonetc.com

USB 3 Camera Software

IDS Imaging Development Systems GmbH’s ver-sion 4.0 software package supports the USB 3uEye CP camera series. A new streaming func-

tion allows transfer of compressed H.264(mpeg4) and mjpeg streams for mobile data ac-quisition, surveillance and remote control of thecamera. All settings to access this feature caneasily be adjusted via uEye Cockpit. Anothernew feature is the uEye programming interfacefor Microsoft .NET. This object-oriented pro-gramming interface is flexible and easy to use,and it allows platform-independent program-ming so that integrating inexpensive and effi-cient applications is as easy as adapting appli-cations when requirements change. V4.0 isavailable for free at www.ueyesetup.com.IDS Imaging Development Systems GmbHusasales@ids-imaging.com

PV Reference Cell Konica Minolta Sensing Americas Inc. haslaunched the AK-300 PV (photovoltaic) refer-ence cell, a dedicated dye-sensitized solar cellused as a standard point of calibration to en-sure consistent measurements of photovoltaiccells. It uses proprietary advanced optical filtertechnology and was designed using an opticalfilter mounted on a stable crystalline siliconsolar cell, rather than using traditional dye ma-terials. Features include a spectral mismatcherror of <1%, durability against solar simulatorlight, and zero errors caused by multiple reflec-tions. The integrated cell has connectors for I-Vmeasurement as well as temperature measure-ment. The built-in temperature sensor can beconnected to a commercially available tempera-

71

bBRIGHT IDEAS

Photonics Spectra July 2012

712_BrightIdeas_Layout 1 6/25/12 4:29 PM Page 71

ture-controlled stage to achieve and maintainthe standard test condition of 25 °C. Includedare the short-circuit current values used forsolar simulator adjustment.Konica Minolta Sensing Americas Inc.marketing@se.konicaminolta.us

Signal Analyzer

Agilent Technologies Inc.’s EXA millimeter-wavesignal analyzer covers frequencies up to 44GHz; with external mixing, it can cover up to325 GHz. The analyzer is expandable, accom-modates a wide variety of measurement appli-cations and can be easily upgraded. Its porta -bility makes it suitable for applications inaerospace/defense and wireless communica-tions backhaul. The system weighs 16 kg, pro-duces sensitivity of ≤140 dBm/Hz across the V-band (with proprietary smart harmonic mixers)and enables accurate measurement of spursand harmonics. With its good phase-noise per-formance, it meets tight regulations and test requirements for millimeter-wave device designand performance verification. Agilent Technologies Inc.contact _us@agilent.com

TCSPC Module

Aurea Technology has announced the SPD_AT,its new near-infrared time-correlated single-photon-counting (TCSPC) module. The ultra -low-noise and high-quantum-efficiency 900- to 1700-nm device includes a Geiger-mode InGaAs avalanche photodiode and thermoelec-tric coolers that ensure high detection efficiencyof up to 25%. Two versions are available: the SPD_AT_M1 with one channel and theSPD_AT_M2 with two channels. Applications include near-infrared fluorescence spectros -copy and photoluminescence.Aurea Technologyjerome.prieur@aureatechnology.com

Filter WheelsFinger Lakes Instrumentation has introduced itslatest generation of six- and 10-position high-speed filter wheel systems for microscopy appli-cations. The HS-625, HS-1025 and HS-1032deliver filter exchange rates of up to 23 ms fullyloaded. The compact, space-saving design usesadvanced brushless servomotor technology withall circuitry incorporated within the housing. Noadditional control units are required. Systems

are available in configurations accommodating25- or 32-mm filters. The filter wheels are sup-plied with control software and a software de-velopment kit and are compatible with MicroManager and most image analysis programs.Features include a synchronous belt drive, se-lectable speed and an RS-232 communicationsinterface. Mounting interface choices include C-and bayonet-mount, with custom configurationsavailable. Finger Lakes Instrumentationinfo@flicamera.com

Control Center for Vision Systems

Cognex Corp. has released the Explorer controlcenter, which displays a graphical view of allCognex ID readers, and vision and visualizationsystems connected to the network. It incorpo-rates maintenance tools for backing up, restor-ing or cloning systems, and for performingfirmware upgrades. The intuitive point-and-clickinterface is easy to use and requires no training.The control center displays the identity, type andstatus of all Ethernet-connected In-Sight visionsystems, DataMan ID readers and VisionViewdisplay devices on the network. Users can viewdevice settings including IP addresses andfirmware/software versions, execute firmwareupdates, back up and restore multiple systemssimultaneously, clone systems when addingmore to the network, and add licenses for Vi-sionView. The system is available free of chargeto all of the company’s customers. It can bedownloaded at www.cognex.com/explorer.Cognex Corp.john.lewis@cognex.com

VLWIR Filters

Deposition Sciences Inc. has unveiled a line ofvery long wavelength infrared (VLWIR) filtersthat provide high transmittance over the 12-µmto beyond the 22-µm wavelength region. Fabri-cated using a proprietary and precise physicalvapor deposition process, the robust coatings

pass all environmental tests and can be repeat-edly cycled between ambient and cryogenictemperatures without degradation. They areavailable with antireflection coatings in narrow-and wide-bandpass, and in long- and short-wave pass types. They can be applied to a vari-ety of substrates, including germanium, zinc selenide, silicon and indium antimonide. Edgeplacement, transmission blocking ranges andlevels, and operating temperatures and anglescan be customized per specifications. Applica-tions include remote sensing, chemical analysis,astrophysics/astronomy and horizon sensors.Deposition Sciences Inc.solutions@depsci.com

Terahertz SystemAdvanced Photonix Inc.’s T-Gauge terahertz sys-tem was developed for use on the factory floorfor quality and process control during manufac-ture of web processing and converting products.Terahertz energy’s ability to penetrate noncon-ducting materials, combined with the system’shigh-speed data processing, enables nonde-structive inspection of web-based products withfeedback for continuous process adjustments.The nonnuclear system is sensitive to physicaland chemical composition changes in products,can measure single- and multilayer thickness,density and basis weight, and can detect sub-surface defects and delamination. Manufactur-ers can mount proprietary and patented fiber-coupled sensors on a scanning frame withoutcontacting or impeding the product. They alsocan collect more information than was previ-ously possible, resulting in tighter tolerancesand improved quality. The system is aimed atreplacing nuclear gauges. Advanced Photonix Inc.ir@advancedphotonix.com

Single-Wavelength Laser Diode

Eblana Photonics Ltd. has made available a sin-gle-wavelength 2000-nm laser diode modulebased on the proprietary Discrete Mode lasertechnology platform. The optically isolated lasermodule uses a strained quantum well design to provide stable distributed feedbacklike perform-ance. It is available in wavelengths from 1995to 2020 nm and is suited for carbon dioxide detection using the 2004-nm absorption line. It delivers high spectral purity, with a typicalside-mode-suppression ratio of 45 dB, and itprovides good device-to-device wavelength and performance uniformity.Eblana Photonics Ltd.info@eblanaphotonics.com

Tailored Bar Architecture Dilas has developed a modular diode laser con-cept combining high power, high brightness,wavelength stabilization and low weight.

72

b BRIGHT IDEAS

Photonics Spectra July 2012

712_BrightIdeas_Layout 1 6/25/12 4:29 PM Page 72

Through the optimization of semiconductor chipstructures and optical parameters, the tailoredbar (T-Bar) architecture delivers high beamquality and high power using standard micro-optic fast-and slow-axis collimators. The devicecan handle multiple emitters during each manu-facturing step to lessen complexity and enhancereproducibility of the beam quality and the fibercoupling. Lab results have demonstrated thatthe optical output power is scaled from 180 Wcoupled into a 100-µm, 0.22-numerical-aper-ture (NA) fiber up to 1.7 kW coupled into a400-µm, 0.22-NA fiber. A lightweight laser unitwith an output power of more than 300 W for a200-µm, 0.22-NA fiber with a weight vs. powerratio of only 0.9-kg/kW can be produced. Dilassales@dilas.com

15-µm Camera

Flir Systems’ Tau SWIR (short-wavelength in-frared) 15 is a rugged, compact and low-powershort-wave imager incorporating a proprietary15-µm-pixel 640 � 515 InGaAs focal planearray. Designed for defense system developers’SWAP+C requirements in dismounted soldiersystems, and ground and aerial platforms, it ex-hibits sensitivity of <50 e− noise at 20 °C casetemperature and can be operated at integrationtimes of 100 µs. It runs on <4 W, weighs <130g, takes up �130 cm2 of volume and operatesat 30 fps. It supports subwindowing whenhigher frame rates are required. The sensor fea-tures a thinned InGaAs detector that widens thespectral response to 600 to 1700 nm and re-duces blooming when viewing bright objects.The camera produces nearly zero image latencyand is suitable for active-illuminated and range-gated applications. Its optical interfaces supportM42 and C-mount lenses, and data interfacesinclude Camera Link, low-voltage CMOS andNTSC analog video.Flir Systemssales@flir.com

Round LEDs Luminus Devices Inc. is releasing a family ofround LEDs that will accelerate the adoption ofsolid-state technology by displacing conven-tional light sources in high-brightness lightingapplications. The new round LED increases sys-tem-level efficiency by as much as 30%, en-abling customers to use a single LED to replacea 250-W high-intensity-discharge lamp. Appli-cations include medical, machine vision, port -able and retail spot lighting. There are benefitsto fiber-coupled lighting systems, but whereasthe fiber and optic are round, the LED was always square. This is resolved with the roundLED, which will enable replacement of the

300-W xenon lamp in applications such as endoscopy.Luminus Devices Inc.sales@luminus.com

Single-Pulse LED Measurement System

Gigahertz-Optik Inc.’s LED measurement systemcomprises the BTS256-LED tester and LPS-20-1500 LED power supply with S-BTS256-LEDsoftware for single-pulse LED binning. Themeter, power supply and control software driveand measure the test LED in single-pulse modeand record the results. The compact testermeasures luminous flux, and spectral and colordata of LEDs in the visible spectrum. Its bi-tech-nology light sensor offers a fine photometric re-sponse photodiode for wide-dynamic-range fluxdetection. A compact low-stray-light spectrome-ter performs spectral color measurements. Thesensor photodiode makes pulse form profilingmeasurements and operates in fast data loggermode with a 1-ms sampling rate. The tester ispowered via USB when connected to a PC. Themicroprocessor-based current and voltagesource is set up for remote control operation incontinuous-wave or single-pulse mode. Currentand voltage can be measured with 16-bit reso-lution. Gigahertz-Optik Inc.b.angelo@gigahertz-optik.com

FIFO Isolators

Gooch & Housego has launched a line of high-power fiber-in, fiber-out (FIFO) isolators for thepulsed fiber laser market. It complements thecompany’s existing portfolio of high-power fiberlaser components, including kilowatt-class mul-timode fiber combiners; single-mode fused tapcouplers and wavelength combiners; fiber-cou-pled acousto-optic modulators; fiber end capsand mode-field adapters; fiber-in, beam-outisolators; and fiber-coupled second-harmonic-generation modules. The FIFO isolator is usedbetween amplification stages in high-powerpulsed fiber laser systems to isolate the initiallower power stages from backreflected pulses aswell as from parasitic lasing and is designed tooperate at average powers of >20 W.Gooch & Housegoplc@goochandhousego.com

73

bBRIGHT IDEAS

Photonics Spectra July 2012

712_BrightIdeas_Layout 1 6/25/12 4:29 PM Page 73

Fiber-Coupled LED Light Engines

Innovations in Optics Inc.’s LumiBright FC fiber-coupled solid-state LED light engines replacelasers and arc lamps in fiber optic applicationsin industrial, life sciences and laboratory equip-ment. They provide illumination for borescopes,microscopes, machine vision, phototherapy,medical endoscopy and UV curing as well as for gel and blot imagers, real-time polymerasechain reaction systems, cytometers, colonycounters, microplate and gene array readers,evaporative light-scattering detectors for liquidchromatography, and label-free systems usingsurface plasmon resonance. The light enginesfeature patented nonimaging optics and high-brightness LED arrays, available with single ormulticolor options in spectral distribution rang-ing from 365 nm through the near-infrared aswell as broadband white. The small footprintenables integration into OEM or end-user systems configured for tabletop, rack-mounted

and portable handheld devices. Innovations in Optics Inc.kevinc@innovationsinoptics.com

IR Sensor, Thermocouple Interface Kit

IRphotonics’ portable iCure IRT200 Thermo Meteris a noncontact infrared sensor that measures thetemperature of objects based on their emitted in-frared energy. It measures heat and converts itinto an electrical signal that is proportional to thesurface temperature of the cure zone. Workingwith the iCure thermal spot curing system, it in-cludes a power controller and a sensor. It offers atemperature range of �50 to 975 °C and a mea-surement spot down to 0.9 mm. The iCure TCK200USB Thermocouple Interface Kit integrates with itfor precise measurements of temperatures usingcommon contact thermocouples. It can be used tocalibrate the IRT200 and to perform process vali-dation in the lab. It supports up to four J-, K-, E-

and T-type thermocouples; displays temperature inCelsius, Fahrenheit and kelvin; uses terminalblocks to interface to thermocouples with strippedleads; connects directly to iCure via a USB port;and delivers a sampling rate of 40 ms.IRphotonicssales@irphotonics.com

Mini CCD Spectrometer

Horiba Scientific’s VS-7000+ mini CCD spec-trometer outperforms front-illuminated andback-illuminated CCDs, the company says,making it suitable for industrial low-light appli-cations such as fluorescence, emission, ab-sorbance and reflectance. It offers coverage forthree spectral ranges: ultraviolet-visible, visibleand ultraviolet-near-infrared. It also provides ahigh signal-to-noise ratio. The uncooled ultra-compact spectrograph features a back-thinnedCCD with a very deep full well, two height op-tions (300 and 1000 µm) and a USB 2.0 inter-face. Its sturdy single-optic design with a con-

74

b BRIGHT IDEAS

Photonics Spectra July 2012

712_BrightIdeas_Layout 1 6/25/12 4:29 PM Page 74

West®Photonics

Conferences & Courses2–7 February 2013

ExhibitionBiOS Expo: 2–3 February 2013Photonics West: 5–7 February 2013

LocationThe Moscone CenterSan Francisco, California, USA

Technologies- BiOS–Biomedical Optics- OPTO–Integrated Optoelectronics- LASE–Lasers and Applications- MOEMS-MEMS–Micro & Nanofabrication- Green Photonics

Optoelectronics, lasers, micro/nanophotonics, and biomedical optics

Call for PapersSubmit your abstract by 23 July 2012spie.org/pw2013

712_SPIE_PhoWest_Pg75_Layout 1 6/25/12 4:11 PM Page 75

cave grating offers light purity, and with nomoving parts or shutter, it is reliable for OEMintegration. Horiba Scientificjoanne.lowy@horiba.com

29-Megapixel Camera

Imperx Inc. has introduced its four-tap Bobcatcamera series. Led by the 29-megapixel ICL-B6640 Bobcat, the cameras operate over a tem-perature range of �40 to 85 °C and offer amean time between failures of >660,000 h at40 °C. The B6640 produces 6600 � 4400-pixelresolution and operates at 5 fps at full resolu-tion. Available in monochrome, color and True-sense color, with 8-, 10- and 12-bit output, the programmable camera consumes 7.8 W. It measures 60 � 60 � 53 mm, is lightweightand is enclosed in a rugged housing. It is suit-able for military, industrial, medical and scien-

tific applications. Standard features include Baseor Medium Camera Link, binning of up to eightpixels horizontally and vertically for variableimage resolution, a Truesense Imaging KAI-29050 sensor, eight independent areas of interest and five triggering modes. Imperx Inc.sales@imperx.com

Digital Microscope

Keyence Corp. of America has released theVHX-2000 digital microscope, which integrateszoom optics with a CCD camera, a 17-in. LCDmonitor, a light source, a controller and soft-ware to streamline testing and improve inspec-tion speed. Magnification ranges from 0.1� to5000�, and supported lighting techniques in-

clude bright- and dark-field, transmitted, polar-ized and differential interference observation. Acolor filter wheel allows users to choose a spe-cific wavelength of light for their samples, and asuperresolution mode combines the blue filterwith proprietary pixel shift technology for high-resolution imaging. The microscope can beequipped with a motorized X-Y stage and mo-torized Z-axis lens control. The image stitchingfunction can be completed with the push of abutton to produce up to a 20,000 � 20,000-pixel image that expands the viewing area. Keyence Corp. of Americamicroscopes@keyence.com

Light Measurement Systems

Labsphere Inc. has announced the illumia andillumia pro series LED and light-measurementsystems. They measure the characteristics ofLEDs, arrays, and solid-state and traditionallighting products, and offer a choice of four

76

b BRIGHT IDEAS

Photonics Spectra July 2012

The latest in photonics for researchers, engineers,

product developers, clinicians and others in medicine,

biotechnology and other life sciences.

Subscribe at www.Photonics.com/Subscribe

From the publisher of Photonics Spectra magazine.

MICROSCOPY

SPECTROSCOPY

IMAGING

OPTICS

LASERS

712_BrightIdeas_Layout 1 6/25/12 4:29 PM Page 76

spectrometers and integrating spheres rangingin size from 25 to 195 cm. The systems measuretotal spectral flux, luminous flux, radiant flux,chromaticity, correlated color temperature, colorrendering index, peak and dominant wave-length, and luminous efficacy. With the additionof a thermoelectric temperature control andmonitoring component, the illumia pro also per-forms thermal, optical and electrical characteri-zation. Proprietary MtrX-SPEC software deliversspectral results in milliseconds. The company’sNIST-traceable, NVLAP-accredited calibratedlamp standards allow manufacturers to moveproduct development from design to marketmore quickly with in-house testing of thermal,optical and electrical properties.Labsphere Inc.labsphere@labsphere.com

Laser Tracker Measurement

Hexagon Metrology’s Version 1.1 firmware pro-vides enhancements for the Leica AT401 Ab-solute Tracker, which now features full-speeddigital readout for dynamic laser tracker mea-surement and free-form surface inspection. Theportable 3-D system enables high-speed meas-urements for large-scale inspection, componentadjustment, alignment, and building of jigs andfixtures. It is used in inspection and tool buildingfor oversize components in the aerospace, nu-clear, and solar and wind energy industries. Theupgrade introduces “outdoor mode,” which in-creases performance when the tracker is used inrain or snow. Other improvements include theuse of several reflectors in view of the sensor atthe same time. The laser tracker’s built-in WiFican be used in a company’s encrypted WiFi in-frastructure, even with several sensors in thesame network. The firmware allows the operatorto quickly see where reflectors are placed. Hexagon Metrologyinfo@hexagonmetrology.us

Purged UV SpectrophotometerMcPherson Inc. has launched its latest VUVASscientific-grade spectrophotometer, which pro-vides stable measurements over time. With a

long lamp life at short ultraviolet wavelengths(120 nm), it is suited to analysis of doped andcrystalline materials as well as of deep-UV op-tics and coatings. It provides direct optical char-acterization of transmission, variable angle re-flectance and gas cell absorbance. It offersreproducible wavelength control throughout the120- to 350-nm region, and sensitive signal re-covery with “lock in” detectors controlled bysoftware. McPherson Spectrometer Control Soft-ware provides single-point control for scanningand data acquisition. Sample contamination isminimized, and lamp life is extended via purgecontrols that integrate sensitive oxygen sensorsand automatic low- and high-flow purge gaschannels. Accessories include light sources, detectors and sample chambers. McPherson Inc.mcp@mcphersoninc.com

FTIR Spectrometer Thermo Fisher Scientific Inc.’s Nicolet iS50Fourier transform infrared (FTIR) research-gradespectrometer is an all-in-one materials analysisplatform that can be upgraded from a simpleFTIR bench to a fully automated multispectral-range system that acquires spectra from the far-to the near-infrared. Users can initiate attenu-ated total reflectance (ATR), Raman and NIRmodules, enabling access to these techniquesvia the automatic beamsplitter exchanger. Thediamond ATR interface allows users to obtain IRspectra in seconds, and an in-sample-compart-ment Fourier transform Raman feature includesa video microstage for point-and-shoot Ramanspectroscopy with no fluorescence. A fiber opticand integrating sphere module enables collec-tion of NIR spectra from a variety of bulk sam-ples. Applications include pharmaceutical for-mulation, polymer development, forensics, art conservation, vibrational circular dichroism,polarization-modulation infrared reflection absorption spectroscopy and time-resolvedspectroscopy. Thermo Fisher Scientific Inc.analyze@thermofisher.com

Debris Shields Debris shields from Optical Surfaces Ltd. protecttarget-facing optics located in high-power laserfacilities. Using debris shields to protect final re-flective or refractive focusing high-power opticsextends their lifetime. Manufacturing high-qual-

77

bBRIGHT IDEAS

Photonics Spectra July 2012

712_BrightIdeas_Layout 1 6/25/12 4:30 PM Page 77

ity debris shields requires producing a precisionwavefront on a flexible window with a high di-ameter-to-thickness ratio. Working with glassesincluding BK-7 and fused silica, which offergood homogeneity and transmission from theUV to the near-IR, the company provides shieldsof virtually any shape and thickness. They areavailable with up to a 600-mm diameter, typicalwavefront error of �/10 and surface finish of40-20 to 10-5.Optical Surfaces Ltd.sales@optisurf.com

1350-nm LasersSemiNex Corp. has announced the availabilityof high-power 1350-nm lasers. The company is

offering this wavelength in raw bars, chips, sub-mounts and fiber-coupled packages. The newtechnology benefits medical applications suchas lipid reduction procedures. The 1350-nmbars are standard 19-emitter bars with totalpower >40 W, continuous wave, and slope efficiency >40%. Single-emitter 1350-nm sub-mounts yield 6 W of continuous-wave power,and the fiber-coupled products provide 4.8 W,also continuous wave. SemiNex Corp.info@seminex.com

Machine Vision Lighting

For machine vision automation applications,Multipix Imaging Ltd. has launched the Micro -scan Nerlite Smart Series lighting with a built-incontroller to adjust intensity continuous modeand high-output strobe mode. The series in-cludes the Hi-Brite area/floodlight, diffuse on-

axis lighting (DOAL) and ringlighting. Hi-Britefeatures IP67 industrial sealing and bright LEDs.Versatile 10° spot and 50° flood lens optionsallow them to be used at both near and far dis-tances. DOAL illuminators provide diffuse, uni-form illumination for flat specular surfaces. Withthe coaxial lighting approach, specular surfacesperpendicular to the camera appear bright,while surfaces that are marked or embossedabsorb light and appear dark. The ringlights are for diffuse illumination of surfaces. Withsubtle adjustments to working distance andangle of light delivery, ringlights deliver goodimage contrast.Multipix Imaging Ltd.sales@multipix.com

78

b

THE ECOC EXHIBITION:Bringing the world the latest in optical communications

AMSTERDAM RAI | Exhibition 17 - 19 September 2012

Pre Register and WIN a Kindle 3G REGISTER NOW at www.ecocexhibition.com

BRIGHT IDEAS

Photonics Spectra July 2012

b ANOTHER BRIGHT IDEA

Advertise your new product in Photonics Showcase or in the Spotlight section of Photonics Spectra.

Reach all of our readers in these low-cost, lead-generating features.

Call Kristina Laurin at (413) 499-0514, or e-mail advertising@Photonics.com.

712_BrightIdeas_Layout 1 6/25/12 4:30 PM Page 78

AUGUSTSecond International Conference on Optical, Electronic and Electrical Materials(Aug. 5-7) Shanghai. Contact Conference Secretariat, +86 519 8633 4730; info@oeem.org; www.oeem.org.

Optical MEMS and Nanophotonics Conference (Aug. 6-9) Banff, Alberta,Canada. Contact Megan Figueroa, IEEE Photonics Society, +1 (732) 562-3895;m.figueroa@ieee.org; www.mems-ieee.org.

SPIE Optics + Photonics (Aug. 12-16) SanDiego. Includes NanoScience + Engineering;Solar Energy + Technology; Organic Photonics+ Electronics; and Optical Engineering + Applications. Contact SPIE, +1 (360) 676-3290;customerservice@spie.org; spie.org.

Sixth EOS Topical Meeting on Visual and Physiological Optics (EMVPO 2012)(Aug. 20-22) Dublin. A European Optical Society event. Contact Julia Dalichow, EOS – Events and Services GmbH, +49 511277 2673; emvpo2012@myeos.org;www.myeos.org.

Fifth EPS-QEOD Europhoton Conference:Solid State, Fibre and Waveguide Coherent Light Sources (Aug. 26-31)Stockholm. A European Physical Society Quantum Electronics and Optics Division event. Contact EPS, +33 389 32 9448; conferences@eps.org; www.europhoton.org.

Ninth International Conference on Group IV Photonics (GFP) (Aug. 29-31)San Diego. Contact Rose Ann Bankowski,IEEE Photonics Society, +1 (732) 562-3898;r.bankowski@ieee.org; www.gfp-ieee.org.

SEPTEMBERMIOMD-XI Mid-Infrared Optoelectronics: Materials and Devices (Sept. 4-8) Chicago.Contact Manijeh Razeghi, Northwestern University, +1 (847) 491-7251; miomd-11@northwestern.edu; miomd-11.northwestern.edu.

Speckle 2012, International Conference onSpeckle Metrology (Sept. 10-12) Vigo, Spain.Contact Speckle 2012, Universidade de Vigo,speckle2012@uvigo.es; speckle2012.uvigo.es.

SPIE Photomask Technology (Sept. 10-13)Monterey, Calif. Contact SPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

Nanosystems in Engineering and Medicine(Sept. 10-13) Incheon, South Korea. ContactSPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

XIX International Symposium on HighPower Laser Systems and Applications(Sept. 10-14) Istanbul. Ozgur Tataroglu,Tübitak Mam, +262 677 3133; ozgur.tataroglu@mam.gov.tr; hplsa2012.mam.gov.tr.

International Manufacturing TechnologyShow 2012 (Sept. 10-15) Chicago. Contact

AMT – The Association for Manufacturing Technology, +1 (800) 524-0475; amt@amtonline.org; www.amtonline.org.

Avionics, Fiber-Optics and Photonics Conference (AVFOP 2012) (Sept. 11-13)Cocoa Beach, Fla. Contact Megan Figueroa,IEEE Photonics Society, +1 (732) 562-3895;m.figueroa@ieee.org; www.avfop-ieee.org.

Photonics in Switching 2012 (PS 2012)(Sept. 11-14) Ajaccio, France. Contact Michel Dupire, SEE, +33 1 5690 3709;www.ps2012.net.

JSAP-OSA Joint Symposia (73rd Japan Society of Applied Physics Annual Meeting2012) (Sept. 11-14) Matsuyama, Japan. Symposia held with Optical Society. ContactJSAP, +81 3 5802 0864; jsap-osa-js@jsap.or.jp; www.jsap.or.jp/english.

OSA Fall Vision Meeting 2012 (Sept. 14-16) Rochester, N.Y. Contact MicheleSchultz, Center for Visual Science, University of Rochester, +1 (585) 275-8659; mschultz@cvs.rochester.edu; www.cvs.rochester.edu/fvm_2012.

Laser World of Photonics India (Sept. 14-16) Mumbai, India. Contact Bhupinder Singh, MMI India Pvt. Ltd., +91 9811090 046; bhupinder.singh@mmi-india.in;world-of-photonics.net.

Fifth International Conference on Singular Optics (Sept. 16-21) Sevastopol,Ukraine. Contact A. Volyar, Taurida NationalUniversity, tel./fax, +380 652 230 248; volyar@crimea.edu; singular-optics.org.

15th European Microscopy Congress (Sept. 16-21) Manchester, UK. Contact Royal

Microscopical Society, +44 1865 254 760; general@emc2012.org.uk; www.emc2012.org.

SPRC 2012 Annual Symposium (Sept. 17-19) Stanford, Calif. Contact Stanford Photonics Research Center, +1 (650) 723-5627; photonics@stanford.edu; photonics.stanford.edu.

Metamaterials 2012: Sixth InternationalCongress on Advanced ElectromagneticMaterials in Microwaves and Optics (Sept. 17-22) St. Petersburg, Russia. Contact contact@congress2012.metamorphose-vi.org; congress2012.metamorphose-vi.org.

SPIE Laser Damage 2012 (Sept. 23-26)Boulder, Colo. Contact SPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

ICALEO, 31st International Congress on Applications of Lasers and Electro-Optics(Sept. 23-27) Anaheim, Calif. Contact LaserInstitute of America, +1 (407) 380-1553; icaleo@lia.org; www.icaleo.org.

IEEE Photonics Conference 2012 (Sept. 23-27) Burlingame, Calif. Contact Mary S. Hendrickx, IEEE Photonics Society, +1 (732) 562-3897; m.hendrickx@ieee.org;www.ipc-ieee.org.

SPIE Remote Sensing and SPIE Security +Defence (Sept. 24-27) Edinburgh, UK. Contact SPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

EOS Annual Meeting 2012 (EOSAM 2012)(Sept. 25-28) Aberdeen, UK. A European Optical Society event. Contact EOS – Events and Services GmbH, +49 511 2788 115; aberdeen@myeos.org; www.myeos.org.

HAPPENINGSPAPERSCOMSOL Conference 2012 (October 3-5) Boston Deadline: abstract submission, July 28Authors are invited to present their work in a paper or poster at this conference, which will focus onmultiphysics modeling and simulations using the COMSOL Multiphysics software environment. Sug-gested topics include semiconductor devices; microfluidics; sensors and actuators; and optics, photon-ics and plasmonics. Accepted work will be published in the conference CD, which has a worldwide audience. Contact Jinlan Huang, +1 (781) 273-3322; jinlan.huang@comsol.com; www.comsol.com.

Photonics 2012 (December 9-12) Chennai, India Deadline: submissions, August 15Organizers of the Photonics 2012 International Conference on Fiber Optics and Photonics encourageauthors to submit original research in areas of interest within the field. Topics include biophotonics;optical fiber devices; photonics modeling; ultrafast optics; silicon photonics; solid-state lighting; greenphotonics; diffractive optics; holographic storage; optical signal processing; nonlinear optics; photoniccrystal structures; and plasmonics, nanophotonics and metamaterials. Contact Shanti Bhattacharya,Indian Institute of Technology Madras, +91 44 2257 4438; photonics2012@ee.iitm.ac.in;photonics.res.in.

SPIE Advanced Lithography (February 24-28) San Jose, CaliforniaDeadline: abstracts, September 10Papers are encouraged for this symposium, which is organized into seven conferences: Alternative Li-thography Technologies; Extreme Ultraviolet Lithography; Metrology, Inspection and Process Controlfor Microlithography; Advances in Resist Materials and Processing Technology; Optical Microlithogra-phy; Design for Manufacturability Through Design-Process Integration; and Advanced Etch Technologyfor Lithographic Patterning. Contact SPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

79Photonics Spectra July 2012

712Happenings_Layout 1 6/25/12 3:55 PM Page 79

OLEDs World Summit 2012 (Sept. 26-28) San Francisco. Contact BrianSantos, Smithers Apex (formerly IntertechPira),+1 (207) 781-9618; bsantos@smithers.com;www.smithersapex.com.

Seventh International Conference on Laser Induced Breakdown Spectroscopy (LIBS 2012) (Sept. 29-Oct. 4)Luxor, Egypt. Contact info@libs2012-niles.org;tel./fax: +202 3567 5335; libs2012-niles.org.

22nd International Symposium on Optical Memory (ISOM’12) (Sept. 30-Oct. 4) Tokyo. Contact ISOM’12 Secretariat, c/o Adthree Publishing Co. Ltd.,+81 3 5925 2840; secretary@isom.jp;www.isom.jp.

OCTOBER23rd IEEE International SemiconductorLaser Conference (ISLC) (Oct. 7-10)San Diego. Contact Rose Ann Bankowski, IEEE Photonics Society, +1 (732) 562-3898;r.bankowski@ieee.org; www.islc-ieee.org.

International Congress on Space Optics (ICSO) and International Conference on Space Optical Systems and Applications (ICSOS) (Oct. 9-12)Ajaccio, France. Contact Carte Blanche, +33 5 63 72 30 68; contact@icso2012.com;www.icso2012.com.

LEDs 2012 (Oct. 10-12) San Diego. Contact Erin Morton, Smithers Apex, +1 (207) 781-9633; emorton@smithers.com;www.ledsconference.com.

IONS-12 Naples Conference (Oct. 10-12) Naples, Italy. An event of IONS, the International OSA (Optical Society) Network of Students. Contact IONS Committee,ions@fisica.unina.it; www.ions-project.org.

Neuroscience 2012 (Oct. 13-17) New Orleans. Contact Society for Neuroscience, +1 (202) 962-4000; info@sfn.org;www.sfn.org.

Frontiers in Optics 2012/Laser ScienceXXVIII (Oct. 14-18) Rochester, N.Y. Annual meetings of OSA and American Physical Society/Division of Laser Science, respectively. Contact Optical Society, +1 (202) 416-1907; custserv@osa.org; www.frontiersinoptics.com.

22nd International Conference on Optical Fiber Sensors (OFS-22) (Oct. 15-19) Beijing. Contact general@ofs-22.org; www.ofs-22.org.

Photonex 2012 (Oct. 17-18) Coventry, UK.Contact Clare Roberts, XMark Media Ltd., +441372 750 555; info@enlightenmeetings.com;www.photonex.org.

LIA’s Lasers for Manufacturing Event (LME 2012) (Oct. 23-24) Schaumburg, Ill.Contact Laser Institute of America, +1 (407)380-1553; lme@lia.org; www.lia.org/lmesd.

OPTO (Oct. 23-25) Paris. Contact NadegeVenet, GL events Exhibitions, +33 1 44 31 8257; nadege.venet@gl-events.com; www.optoexpo.com.

SPIE Asia-Pacific Remote Sensing (Oct. 29-Nov. 1) Kyoto, Japan. Contact SPIE,+1 (360) 676-3290; customerservice@spie.org;spie.org.

NOVEMBERFifth International Photonics and OptoElectronics Meetings (POEM 2012)(Nov. 1-2) Wuhan, China. Contact Wuhan National Laboratory for Optoelectronics, +86 27 877 92 227; poem@mail.hust.edu.cn;poem.wnlo.cn.

SPIE/COS Photonics Asia (Nov. 4-7)Beijing. Sponsored by SPIE and the ChineseOptical Society. Contact SPIE, +1 (360) 676-3290; customerservice@spie.org; spie.org.

80

h HAPPENINGS

Photonics Spectra July 2012

For complete listings, visit

www.photonics.com/calendar

Contact your sales representative at (413) 499-0514 or sales@photonics.com

No other industry publication delivers readers like Photonics Spectra –

September Content Focus: Transportation & EnergySpotlight: Imaging Components & SystemsPhotonics ShowcaseWebinar: SolarBonus Circulation: IMTS, ICALEOAd close: July 25, 2012

October Content Focus: ManufacturingSpotlight: Optics & Optics FabricationSneak Preview: Society for Neuroscience

Annual MeetingBonus Circulation: Frontiers in Optics, Photonex,

OPTO 2012Ad close: August 24, 2012

Support your print advertising schedule with great digital opportunities

including photonics.com, Light Matters weekly newscast sponsorship and webinars.

Advertise in Photonics Spectra

712Happenings_Layout 1 6/25/12 3:55 PM Page 80

aaADVERTISER INDEX

81Photonics Spectra July 2012

Photonics Media Advertising Contacts

Please visit our websitePhotonics.com/mediakit for all our marketing opportunities.

Ken TyburskiDirector of SalesVoice: +1 (413) 499-0514, Ext. 101Fax: +1 (413) 443-0472ken.tyburski@photonics.com

New England, Southeastern US, FL, Midwest, Rocky Mountains, AZ & NMRebecca L. PontierAssociate DirectorVoice: +1 (413) 499-0514, Ext. 112Fax: +1 (413) 443-0472becky.pontier@photonics.com

NY, NJ & PATimothy A. DupreeRegional ManagerVoice: +1 (413) 499-0514, Ext. 111Fax: +1 (413) 443-0472tim.dupree@photonics.com

Northern CA, AK, NV, Pacific Northwest,Yukon & British Columbia Joanne C. GagnonRegional ManagerVoice: +1 (413) 499-0514, Ext. 226Fax: +1 (413) 443-0472joanne.gagnon@photonics.com

Central CA, Southern CA & HI Tracy L. ReynoldsRegional ManagerVoice: +1 (413) 499-0514, Ext. 104Fax: +1 (413) 443-0472tracy.reynolds@photonics.com

Eastern CanadaMaureen Riley MoriartyRegional ManagerVoice: +1 (413) 499-0514, Ext. 229Fax: +1 (413) 443-0472riley.moriarty@photonics.com

Europe, Israel & South Central USOwen BrochRegional ManagerVoice: +1 (413) 499-0514, Ext. 108Fax: +1 (413) 443-0472owen.broch@photonics.com

Austria, Germany & LiechtensteinOlaf KortenhoffVoice: +49 2241 1684777Fax: +49 2241 1684776olaf.kortenhoff@photonics.com

Asia (except Japan)Hans ZhongVoice: +86 755 2872 6973Fax: +86 755 8474 4362hans.zhong@yahoo.com.cn

JapanScott ShibasakiVoice: +81 3 5225 6614Fax: +81 3 5229 7253s_shiba@optronics.co.jp

Reprint ServicesVoice: +1 (413) 499-0514Fax: +1 (413) 443-0472editorial@photonics.com

Mailing addresses:Send all contracts, insertion orders and advertising copy to:Laurin PublishingPO Box 4949Pittsfield, MA 01202-4949

Street address:Laurin PublishingBerkshire Common, 2 South St.Pittsfield, MA 01201Voice: +1 (413) 499-0514Fax: +1 (413) 443-0472advertising@photonics.com

Aero Research Associates Inc. ....................73www.aerorese.com

Aerotech Inc. .........................32www.aerotech.com

Alluxa ...................................38www.alluxa.com

Andor Technology .................67www.andor.com

Applied Scientific Instrumentation Inc. .............28www.asiimaging.com

BaySpec Inc. .........................50www.bayspec.com

Bristol Instruments Inc. ............16www.bristol-inst.com

Cargille Laboratories ..............30www.cargille.com

Chroma Technology Corp. ................66www.chroma.com

CVI Melles Griot ....................29www.cvimellesgriot.com

DataRay Inc. .........................49www.dataray.com

Deposition Sciences Inc. .........67www.depsci.com

DiMaxx Technologies .............66 www.dimaxxtech.com

DRS Technologies Inc. ..............7www.drs.com

Edmund Optics ......................19www.edmundoptics.com

Electro-Optics Technology Inc. ...................77www.eotech.com

Energetiq Technology Inc. .......36www.energetiq.com

Fermionics Opto-Technology ................45www.fermionics.com

First Sensor Inc. .....................27www.first-sensor.com

FLIR Systems Inc. ....................39www.flir.com

4D Technology Corporation ....68www.4dtechnology.com

G-S PLASTIC OPTICS .............67www.gsoptics.com

Gooch & Housego .................22www.goochandhousego.com

Hamamatsu .............................9www.sales.hamamatsu.com

Innovation Photonics ..............66www.innpho.com

ISP Optics ...........................CV3www.ispoptics.com

LaCroix Optical Co. ...............37www.lacroixoptical.com

Laser Institute of America .......74www.laserevent.org

Kurt J. Lesker Co. ...................57www.lesker.com

LightMachinery Inc. ..........14, 24www.lightmachinery.com

LightWorks Optics Inc. .........CV2www.lwoptics.com

Mad City Labs Inc. .................40www.madcitylabs.com

Master Bond Inc. ...................14www.masterbond.com

Mightex Systems ....................33www.mightexsystems.com

Mildex Inc. ............................67www.mildex.com

New Infrared Technologies .......................66www.niteurope.com

Newport Corporation .......23, 26www.newport.com

Nexus Business Media Ltd. .....78www.ecocexhibition.com

Novotech Inc. ........................30www.novotech.net

Optimax Systems Inc. .............61www.optimaxsi.com

Osela Inc. .............................68www.oselainc.com

PCO-TECH Inc. ......................13www.pco-tech.com

Photonics Media ..............31, 69, 76, 80www.photonics.com

PI (Physik Instrumente) L.P. .......68www.pi.ws

Pico Electronics Inc. ................54www.picoelectronics.com

PicoQuant GmbH ..................18www.picoquant.com

piezosystem jena GmbH ........80www.piezojena.com

Precision Glass& Optics .......................15, 67www.pgo.com

Qioptiq Inc. .............................8www.qioptiq.com

Research Electro-Optics ..........17www.reoinc.com

Reynard Corporation .............44www.reynardcorp.com

Schneider Optics Inc. .............28www.schneiderindustrialoptics.com

Siskiyou Corporation ..............65www.siskiyou.com

Smithers Apex .......................35www.oledsworldsummit.com

Spectra-Physics, A Newport Corporation Brand ..........................6, CV4www.newport.com

SPIE International Society for Optical Engineering ..................25, 75www.spie.org/aboutop

Stanford Research Systems Inc. ..........................3www.thinksrs.com

Sutter Instrument ....................33www.sutter.com

Swift Glass Co. Inc. ................68www.swiftglass.com

Sydor Optics Inc. ...................40www.sydor.com

tec5USA Inc. .........................48www.tec5usa.com

Tohkai Sangyo Co. Ltd. ..........24www.peak.co.jp

TOPTICA Photonics Inc. ..........41www.toptica.com

TRIOPTICS GmbH ..................66www.trioptics.com

TRUMPF Inc. ..........................11www.us.trumpf.com

Westech Optical Corporation ........................68www.westechoptical.com

Z&Z Optoelectronic Tech. Co. Ltd. ......................71www.zzoptic.com

Zygo Corp. ...........................51www.zygo.com

712AdIndex_Layout 1 6/25/12 3:51 PM Page 81

p PEREGRINATIONS

Uncooled IR camera reveals mysteries of spaceEven three years after its liquid helium

cooling supply was exhausted, themaverick Infrared Array Camera

(IRAC) on NASA’s Spitzer Space Tele-scope continues to capture new and won-drous views of the universe.

Launched in 2003, the Spitzer was de-signed to study objects within our solarsystem and beyond, to the most distantparts of the universe. Most of the tele-scope’s other instruments lost function inspring 2009, when the “cold mission”ended.

Now in the “warm mission,” IRAC isusing its two shortest-wavelength infraredsensors to image cosmic regions not visi-ble through optical telescopes, allowingscientists to see cooler objects in space,such as failed stars, exoplanets, giant mo-lecular clouds and organic molecules thatcould hold the secret to life on other plan-ets, according to the mission overview.

To celebrate the warm mission’s “1000days of infrared wonders,” NASA has re-leased the 10 best IRAC images (some ofwhich include data collected during thecold mission, when all four of the cam-era’s infrared sensors were functioning).

The full Spitzer system consists of thecryogenic telescope assembly, includingan 85-cm telescope and three scientific in-struments, as well as the spacecraft, whichcontrols the telescope, provides power,handles data and communicates withEarth. The mission is managed by the Jet Propulsion Laboratory at California Institute of Technology in Pasadena.

Thanks to the quality of the imagesIRAC has produced, NASA’s Senior Re-view Panel has recommended extendingthe Spitzer warm mission through 2015.

“IRAC continues to be an amazingcamera, still producing important discov-eries and spectacular new images of theinfrared universe,” said principal investi-gator Giovanni Fazio of the Harvard-Smithsonian Center for Astrophysics inCambridge, Mass.

82 Photonics Spectra July 2012

Caren B. Lescaren.les@photonics.com

Several stellar nurseries can be seen in this giantcloud. IRAC can measure the warm dust and peer into it to study the processes of new star formation. The image shows the edge of a regionnear the Perseus constellation. Courtesy of NASA, JPL-Caltech and Harvard-Smithsonian Center for Astrophysics.

This “tornado” nebula is one of the mysterious objects discovered through the lens of the InfraredArray Camera (IRAC) on the Spitzer Space Telescope. The camera is sensitive to light emittedfrom shocked molecular hydrogen (seen in green). Scientists think the formation arises from an outflowing jet of material from a young star that has created shock waves in surrounding gas anddust. Courtesy of NASA, JPL-Caltech and J. Bally (University of Colorado).

For more images from NASA’s Spitzer Space Telescope, visit www.spitzer.caltech.edu.

IRAC captured two galaxies – the Whirlpool and its companion – in collision 23 million light-yearsfrom Earth. The camera sees the main galaxy as reddue to warm dust – a sign of active star formation,probably brought about by the collision. Courtesy of NASA, JPL-Caltech and R. Kennicutt (University of Arizona).

712Peregrinations_Layout 1 6/25/12 4:14 PM Page 82

THE INFRAREDCOMPANYTHE INFRAREDCOMPANY

IR OPTO-MECHANICAL DESIGN

IR LENS ASSEMBLIESIR LENS ASSEMBLIESIR CATALOG

IR CUSTOM OPTICS

IR CRYSTAL OPTICS

IR COATINGS

ISP OPTICS USA: 50 South Buckhout St., Irvington NY, 10533IR@ispoptics.com www.ispoptics.com Tel: (914) 591-3070

ISP OPTICS ISRAEL: 5 Shimshon St, Bldg B, Suite 5, Petach Tikva, 49517, Israel IR@ispoptics.com Tel +972 391 99876

ISP OPTICS LATVIA: 24a Ganibu Dambis, korp. 13 Riga, LV-1005,Latvia IR@ispoptics.com Tel +371 67 323 779

712_ISPOptics_PgCVR3_Layout 1 6/25/12 4:00 PM Page CVR3

712_Newport_#1_PgCVR4_Layout 1 6/25/12 4:01 PM Page CVR4