Optical MEMS for Earth Observation: an efficient optical ...
Transcript of Optical MEMS for Earth Observation: an efficient optical ...
![Page 1: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/1.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Frederic Zamkotsian1, Arnaud Liotard2, Patrick Lanzoni1, Thierry Viard2, Wilfried Noell3, Benedikt Guldimann4, Marco Freire4, Stefan Kraft4
Laboratoire d’Astrophysique de Marseille, FranceThales Alenia Space, France
EPFL, Switzerland ESA / ESTEC, Netherlands
Optical MEMS for Earth Observation: an efficient optical cloud removal technique
100 200 300 400 500 600 700
0.01
0.02
0.03
0.04
0.05
Spectrometer
FPA
Reflective slit
![Page 2: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/2.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Instrumental needs using micro-opto-electro-mechanical systems (MOEMS)
Wavefront control- Deformable mirrors
Object selection- Programmable slits
Spectral domain application- Programmable gratings
Phase
Intensity
Wavelength
Instrumental needs
![Page 3: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/3.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
MOEMS for Earth Observation
First phase: collecting all necessary data Earth observation instruments or payloadsExisting and potential optical MEMS componentsSecond phase Pre-selection of at least 6 optical payloads following
three different philosophies - pre-selection of 2 market-pull concepts- pre-selection of 3 techno-push concepts- pre-selection of 1 concept coming from outside Earth Observation
Final selection of the 2 most promising optical payloadThird phaseDetailed design of the 2 promising conceptsSynthesis of the study
![Page 4: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/4.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Tiltable micromirror arrayActive on intensityHigh contrastDigital mode only : light is switched between ON and OFF positions
Tiltable micromirror arrays
![Page 5: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/5.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Single crystalline micromirror array for next generation IR multi-object spectrographCollaboration between LAM and EPFL Goal: high contrast 1500:1 Fill factor > 90 % obtainedConcept
Electrostatic actuationPrecise tilt angle (landing beams)
RealizationCombination surface and bulkmicromachiningWafer level bonding of two wafers: one for th mirrors, one for the electrodes
MIRA
![Page 6: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/6.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Surface qualityOn 100µm x 200µm micromirrors: deformation < 10 nmTilt angle precision < 1 arcminActuation voltage < 100 V
Environmental testsVacuum (10-6 mbar)92K and 162 K Mirrors tiltSurface quality < 30 nm PtV in cryo
92K0V
92K90V
MIRA
![Page 7: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/7.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Most popular MOEMS deviceMicromirrors
2048x1080 mirrors individually adressablesPitch 13,68µm Tilt angle: 12°
Numerous applications Main application: image display Design modification not possible
Spatial qualification test (ESA contract)-40°C in vacuum (10-5 mbar)Micromirrors hold in position during > 1500 sDMD fully operationalLife test during 1038h, radiations, vibrations No showstopper for space use
DMD from Texas Instruments
![Page 8: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/8.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Programmable micro-diffraction gratings (PMDG)Action on phaseBased on 200µm x 4µm ribbons, with piston mouvmentDigital mode: light modulated between ON and OFF positionsAnalog mode: ribbons move in order to cancel partially the input light (“gray” scales)
PMDG
Incident lightReflected light
Incident lightReflected light
Incident lightDiffracted light
Incident lightDiffracted light
![Page 9: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/9.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
PMDG from Silicon Light Machines (ESA study)1086 pixels
6 ribbons (3 pairs) / pixel3 fixed ribbons / 3 piston ribbonsPixel pitch 25.5µmRibbon width / gap: 3.775µm / 0.475µmRibbon length 220µmActive area 75 x 28254 µm2
Window with visible coatngMonted on PCBHeat sink on the backVmax = 385V Coded on 1024 levels (10 bits)
PMDG from SLM
![Page 10: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/10.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Ribbons images / localized sourceFiltering in Fourier plane
PMDG in operation
![Page 11: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/11.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
PMDG performances
Device for wavelength selectionFully programmableSteep edge filters, contrast > 30Long term stability and reproducibilityDynamical response (1 MHz)
![Page 12: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/12.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Micro-deformable mirrors (MDM), action on wavefront (phase)Actuators arrayContinuous mirrorBoston Micromachines devicesUp to 4096 actuators, up to 5µm stroke.
MDM
h
l
Mirror Surface
ActuatorsSubstrate
Anchoring post
![Page 13: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/13.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
First promising concept based on MOEMS : Cloud remover
©ESA Source = MERIS
![Page 14: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/14.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
MERIS return of experience :Push-broom spectro-imager for Earth monitoring
Clouds in the field-of-view generates massive straylightSun-glint completely saturates the detector.
Cloud remover
![Page 15: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/15.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Spectrometer characteristics (spectrum : 400 nm -> 1020 nm)
Classical design : slit dimensions17mm x 20 microns740 columns
New design : dynamical reflective slitBased on a micro-mirror arrayEnable to reject bright sources
Towards spectrometer
Towards light trap
Cloud remover
![Page 16: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/16.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Spectrometer characteristics (spectrum : 400 nm -> 1020 nm)Classical design : transmissive slitNew design : reflective slit
Compliant with the opto-mechanicaldesignEnable to reject bright sources
Spectrometer
FPA
Reflective slit
Cloud remover
![Page 17: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/17.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Straylight analysisComplete simulations with ASAPSpectrometer nominal designStraylight ratio :
Straylight level / useful signal
Slit 74x10pLMAX LREF
Pixel 740 Pixel 1
X
Z
YX
Z
YLmaxLref
-0,1
0
0,1
0,2
0,3
0,4
0,5
0,6
0,7
0 100 200 300 400 500 600 700 800
Pixels
Stra
ylig
ht r
atio Oa1
Oa5Oa12Oa19Oa21
60 %
Straylight without bright sources remover
-0,01
0
0,01
0,02
0,03
0,04
0,05
0,06
0 100 200 300 400 500 600 700 800
Pixels
Stra
ylig
ht r
atio Oa1
Oa5Oa12Oa19Oa21
Straylight with bright sources remover
6 %
Cloud remover
![Page 18: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/18.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
CAD view
Focal plane
Catadioptric objective
Concave grating MEMS / entrance slit
MIRA board
Cloud remover
![Page 19: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/19.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Neutral density plates
FOV = clouds + scene
Straylight simulator
L4
Output pupil
CCD camera
White source
DMD
L1
L2
L3
Input pupil
Slit 74x10pLMAX LREF
T6
Slit 74x10p LMAX LREFT6B (X=10)
T6C (X=20)
T6D (X=30)
X times 10p (upon a total de 74)
Pixel 740 Pixel 1
Pixel 740 Pixel 1
X
Z
YX
Z
Y
X
Z
YX
Z
Y
Slit 74x10p LMAX LREFT6Y (X=-38 – out-of-field)
T6Z (X=-30)
X times 10p (upon a total de 74)
Pixel 740 Pixel 1
X
Z
YX
Z
Y
Cloud Ground
Spectrograph simulator
FOV simulator
Cloud remover: demonstration @ LAM
![Page 20: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/20.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Bright sources remover experiment results
Profile of the field-of-viewScene @ Lref (left part)Bright source @ Lmax (right part)
green curve: programmable slit is all ONblue curve: the micro-mirrors located on the bright area are switched OFF
Close-up view of the transition areaLight blue curve: perfect scene without the bright source
0 200 400 600 8000
0.2
0.4
0.6
0.8
1
Camera pixels
Nor
mal
ized
inte
nsity
S l i t 7 4 x 1 0 pL M A X L R E F
P i x e l 7 4 0 P i x e l 1
X
Z
YX
Z
YLmaxLref
Cloud remover: demonstration @ LAM
![Page 21: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/21.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Bright sources remover experiment results
Profile of the field-of-viewScene @ Lref (left part)Bright source @ Lmax (right part)
green curve: programmable slit is all ONblue curve: the micro-mirrors located on the bright area are switched OFF
Close-up view of the transition areaLight blue curve: perfect scene without the bright source
0 200 400 600 8000
0.2
0.4
0.6
0.8
1
100 200 300 400 500 600 700
0.01
0.02
0.03
0.04
0.05
Camera pixels
Nor
mal
ized
inte
nsity
S l i t 7 4 x 1 0 pL M A X L R E F
P i x e l 7 4 0 P i x e l 1
X
Z
YX
Z
YLmaxLref
Cloud remover: demonstration @ LAM
![Page 22: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/22.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Bright sources remover experiment results
Profile of the field-of-viewScene @ Lref (left part)Bright source @ Lmax (right part)
green curve: programmable slit is all ONblue curve: the micro-mirrors located on the bright area are switched OFF
Close-up view of the transition areaLight blue curve: perfect scene without the bright source
0 200 400 600 8000
0.2
0.4
0.6
0.8
1
100 200 300 400 500 600 700
0.01
0.02
0.03
0.04
0.05
Camera pixels
Nor
mal
ized
inte
nsity
MIRA
Cloud remover: demonstration @ LAM
![Page 23: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/23.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Second promising concept based on MOEMS : Tuneable spectrometer with field of view
©ESA Source = MERIS
V sat
![Page 24: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/24.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Spectrometer concept for push broom acquisitionUse of a micro mirrors array
One dimension for the FOVOne dimension for the spectral dispersion
Entrance slit
Linear detectorarray
Identical gratings
DMD
DMD for spectral tailoring with FOV
![Page 25: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/25.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Entrance slit
Linear detectorarray
Identical gratings
DMD
DMD for spectral tailoring with FOV
![Page 26: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/26.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
MOEMS (DMD) characteristicsMicro mirror dimension around 15 µm x 15 µmNumber of micro mirrors in spectral direction around 1000Number of micro mirrors in spatial direction around 2000
Design parameters (other operating points are possible)Spatial resolution = 5 m (for altitude = 700 Km)Total field = 10 Km (2000 pixels)Total bandwidth = 200 nm (ex : from 400 nm to 600 nm)Theoretical spectral resolution can be tuned from 0,2 nm to 200 nm
Instrument characteristics (for here above operating point)Entrance pupil dimension ΦPE = 270 mm Afocal magnification ratio G around 5 (grating size = 54 mm)Focusing focal length fFOC = 380 mm (F-number 7.6)Grating period around 300 lines/mm for visible range
DMD for spectral tailoring with FOV
![Page 27: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/27.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
VolumeX :669 Y : 480 Z : 568.
DMD for spectral tailoring with FOV
Bench demonstrator will be developed within a CNES study
![Page 28: Optical MEMS for Earth Observation: an efficient optical ...](https://reader033.fdocuments.in/reader033/viewer/2022061102/629c4b5ae62b0d255049286c/html5/thumbnails/28.jpg)
Frederic Zamkotsian 8th ESA MNT Round table, Noordwijk, 15 – 18 October 2012
Space optical payloads can benefit from MOEMS technology
Optical MOEMS can bring new services/functionalities in Earth ObservationTwo promising concepts have been proposed and studied:- Cloud removal based on Digital Micro-mirror Array- Tunable spectrometer with field-of-view based on TI’s DMD
MOEMS for Earth Observation
100 200 300 400 500 600 700
0.01
0.02
0.03
0.04
0.05
Spectrometer
FPA
Reflective slit