Nanomaterials and their Optical Applications · Lecture : Nanomaterials and their optical...

[email protected] Lecture 11 http://www.iap.uni-jena.de/multiphoton

Nanomaterials and their Optical Applications

Winter Semester 2012 -2013

Lecture 11

[email protected]

[email protected] Lecture 11

Schedule until the end of the semester 2

11 14.01.2013 Nanomarkers12 21.01.2013 Seminars presentations by students (2)13 28.01.2013 Seminars presentations by students (2)x 04.02.2013 no lecture

Lecture, Mondays 16-17.30

Turn in HW 4 on Tuesday 20.01.2013

Seminar, Tuesdays

p / / Q 7 22.01.2013

Examination : February 14th Beutenberg campus, IAP, 14.30-16.30


Choose your slot 3

Lecture : Nanomaterials and their optical applications

Date Room Time Speaker Title of the talk

21.01 IAP 16.00 Yera Ussembayev Plasmonic nanoparticles for biomedicine

16.30 Sebastian Unger Nanodiamonds

17.00 Zhi Upconversion nanoparticles

28.01 IAP 16.00 Pavlo Kliniev Nanowires as biosensors

16.30 Can Boran Akdal SPASERs

17.00 Wondimu Alemu High resolution microscopy


Location Institute of Applied Physics 4


Outline: Nanomarkers 5

• Contrast in imaging modalities

• Static versus dynamic probes

• Dynamic markers

• Multiphoton nanomarkers : SHRIMPs

www.spps.fi/


Possible contrast mechanism for imaging 6


Possible contrast mechanism for imaging 7


Contrast agents 8

Tissue itself Melanin , collagen

Dyes Nanoparticles Quantum dots


Contrast agents 9

Goal of biomedical imaging: structural and functional information


Contrast agents 10


Contrast agents: dynamic probes 11

Scattering probes: static, thus background noise from scattering of the tissues

Dynamic probes: modulated externally by slight modulation, then the unmodulated background can be filtered out efficiently

Contrast agents: paramagnetic particles, 20-30 nm with a magnetic susceptibility of χ=1 In tissue χ< 10-5

Contrast agents: iron oxide like magnetite, already used in MRI

Under a high magnetic field gradient… What happens ?



Optical coherence tomography (OCT) to detect the changes: The optical setup typically consists of an interferometer with a low coherence, broad bandwidth light source. Light is split into and recombined from reference and sample arm, respectively.

optical ultrasound !

The key benefits of OCT are:

• Live sub-surface images at near-

microscopic resolution

• Instant, direct imaging of tissue

morphology

• No preparation of the sample or subject

• No ionizing radiation


Magnetomotive OCT 13

Stephen A. Boppart, M.D., Ph.D., University of Illinois at Urbana-Champaign


Imaging applications: Two-photon confocal 17

17

The Journal of Cell Biology, Volume 105, 1987

Fertilized egg of a sea urchin stained with antitubulin. Scale bar, 50 um.

Conventional vs Confocal microscopy

Single-photon vs two-photon confocal

• Small excitation volume • Longer wavelength


Some history 18

18

1986 First biological samples

1974 First SHG microscopy

Freund et al.. Biophys. J. 50, 693 1986

1999 High resolution SHG

Campagnola et al Biophys. J. 77, 3341 (1999).

Hellwarth et al, Opt Comm, 12, 3, 1974

rat tail tendon

1978 First scanning image

Gannaway et al., OQE, 10, 435, 1978


What is the Second Harmonic Generation (SHG) ? 19

19

Take the simplest atom: hydrogen Put it into an electric field

where α is the answer of the atom to electric field

Microscopic view: 1 atom

Macroscopic view: N atoms

p Eα=

You end up with a dipole moment

the macroscopic dipole moment (per unit volume) is called the POLARIZATION :

Term responsible of second harmonic generation Only present in special material that do not have a center of symmetry

2 30 1 0 2 0 3 ...P E E Eε χ ε χ ε χ= + + +

• 3rd-order : multiphoton absorption, third harmonic generation, coherent anti-Stokes Raman scattering

• 1st-order : absorption and reflection

• 2nd-order: SHG, sum and difference frequency generation, hyper-Rayleigh


20

20

Energy diagram

ω

ω 2ω

ω

ω

Real state

< 2ω

Ground state

Non-radiating relaxation

2-photon fluorescence

Ground state

Virtual state

SHG

Purely scattering mechanism

ω 2ω

Excitation and emission spectra Laser pump

(> 450 nm) 800 850 900 400 425 450

SHG 2-photon fluorescence

directional Non directional

What is the Second Harmonic Generation (SHG) ?


Endogenous SHG : no staining 21

C. elegans

Green SHG from collagen

Red is autofluorescence

Green: SHG (collagen) Red: endogenous 2PEF Pink: THG

C. elegans

Human colon adenocarcinoma

Rat lung tissue

Edward Brown and Rakesh Jain Massachusetts General Hospital

Nature Methods 3, 47 (2006)

50 μm.

@ BIOP

@ BIOP


Endogenous SHG : no staining 22

C. elegans

C. elegans

50 μm.

@ BIOP

@ BIOP

Microscope settings: Pump at 812 nm Detection in reflection with filter set

Cut the pump

Narrow band pass at 406 nm


Endogenous SHG vs SH nanoprobes 23

C. elegans

C. elegans

50 μm.

@ BIOP

@ BIOP

Label with SHRIMPs

Second Harmonic Radiation IMaging Probes

SHRIMPs

• Flexibility to target any type of cells or tissue • No phase matching issue due to the particle

size smaller than the wavelength

HeLa cells


Who are SHRIMPs ? 24

24

Crystalline organic-inorganic hybrid particles

Bonacina et al. Appl. Phys. B 2007

Delahaye, et al. Chem. Phys. Lett. 2006

Nakayama et al., Nature 2007

KNbO3

Fe(IO3)3

100 nm

BaTiO3

Hsieh et al, Opt. Exp. 2009

Zielinski et al. Small 2009

CdTe/CdS BaTiO3 /Au

Pu et al, PRL 2010

Le Xuan APL 2006

KTP

Kachynski et al. J. Phys. Chem. C 2008

ZnO

Non centrosymmetric material = space group lacking an inversion center


Challenges in Biomedical Imaging 25

25

Life processes are … • Extremely complex • Highly dynamic • KEY: imaging probes

The wish list for “ideal” probes … • Small (the smaller the better) • Sensitive (easily detected) • Sustainable (no bleaching) • Stable (no blinking) • Fast (quick response) • Scalable (no signal saturation) • Biocompatible (no toxicity) • …

GFPs

www.Invitrogen.com

QDs Dr. Kalju Kahn at UCSB

SHRIMPs


Advantages of SHRIMPs 26

26

Long-term observation: Due to the SHG physical mechanism over virtual energy state

Flexibility in excitation wavelength: SHG is a nonresonant process

Coherent signals: interferometric detection techniques possible, such as holography

Narrow signal bandwidth: more effectively suppress the background.

Ultrafast response time: in the subfemtosecond range

Biocompatibility: little toxicity and excellent biocompatibility to cells and tissues.

Laser pump

(> 450 nm) 800 850 900 400 425 450

SHG 2-photon fluorescence


BaTiO3 nanoparticles characterization 27

100x NA 1.4

Ti:sapphire oscillator 800nm, 76MHz, 150fs

Peak intensity 1 GW/cm2 100x less than cell damage threshold

SHG: Quadratic power dependency

σ 2p : Two-photon cross section

1GM (Goeppert-Mayer) = 10-50 ⋅ cm4 ⋅ sec / photon)

W2p = σ2p ⋅ (Iincident)2

C. Hsieh, R. Grange, Y. Pu, D. Psaltis, Opt. Express. 17, 2880 (2009)

Total radiated power


BaTiO3 nanoparticles characterization 28

100x NA 1.4

Ti:sapphire oscillator 800nm, 76MHz, 150fs

Peak intensity 1 GW/cm2 100x less than cell damage threshold

Comparison with fluorescent and SH markers

Type Size (nm) σ 2p (GM) GFP < 5 6 QD 10 2’000 - 47’000 BaTiO3 30 8.5 BaTiO3 90 6’500


Plasmonics to engineer a resonance 29

29

SHG enhancement > 1000 x Tunability with thickness

Noble metal nanoparticles or shells: oscillation of conduction electrons at the surfaces generating a strong resonance at optical frequencies

Scientific American 2007


Plasmonics to engineer a resonance 30

Y. Pu, R. Grange, Ch.-L. Hsieh, and D. Psaltis, Physical Review Letters, 104, 2010.

Amine Au seeds Shell Bare SHRIMPs

SEM pictures at different stages

Chemical synthesis of the nanoshell


Superresolution microscopy 31

http://zeiss-campus.magnet.fsu.edu/articles/superresolution/introduction.html



stimulated emission depletion (STED)

http://zeiss-campus.magnet.fsu.edu/tutorials/superresolution/stedconcept/index.html



Single-Molecule Localization Microscopy

http://zeiss-campus.magnet.fsu.edu/tutorials/superresolution/stedconcept/index.html


SHG imaging of semiconductor nanowires 34

GaAs Nanoneedles

Chen et al., Appl. Phys. Lett. 2010

Point-by-point scanning techniques: confocal or near-field imaging

GaN

Long et al., Nano Lett. 2007

2 µm

Laser 806 nm

SHG 403 nm

ZnO

Johnson et al., Nano Lett. 2002


How to map the electric field distribution ? 35

GaAs Nanoneedles ZnO

• No whole view

• Slow

• Interaction with tip

Chen et al., Appl. Phys. Lett. 2010

Point-by-point scanning techniques: confocal or near-field imaging

Johnson et al., Nano Lett. 2002


GaAs properties and fabrication 36

• Metal-organic vapor phase epitaxy (MOVPE) system on GaAs wafers

• Au seeds formed upon annealing of a thin Au layer of 2.5 nm thickness

• Tapered and untapered GaAs NWs

G. Brönstrup and et al., Nanotechnology, 22(38):385201, 2011

Au-assisted vapor-liquid-solid (VLS) mechanism

Radius: 75-100 nm Length: up to 15 µm

3 µm

Collaboration with MPI Light & Duisburg University


SHG Far-Field Imaging Setup 37

λ/2

Lens

Sample

Lens

Filters 410 nm

Ti:Sapphire

820 nm 250 fs

10-40 mW

Objective 100x

electron-multiplied CCD

Focal spot on the whole NW

No scanning

3 µm

λ (nm)

1/α

(nm

) Long mean free path @ 820 nm


SHG Far-Field Imaging Setup 38

λ/2

Lens

Sample

Lens

Filters 410 nm

Ti:Sapphire

820 nm 250 fs

10-40 mW

Objective 100x

electron-multiplied CCD

Focal spot on the whole NW

No scanning

3 µm

Mean free path in bulk GaAs = distance at which

the intensity drops to 1/e²:

16.3 nm for λSHG=410 nm

NW

detector

Surface sensitive imaging technique


Far-field SHG imaging of a whole nanowire 39

Nanowire radius determination

Atomic Force Microscopy (AFM)

Radius of 78.5 ± 2 nm.

Periodic SHG reponse

Distances (µm)

SH

G p

ower

(W)

576 nm

(a)

(b)

(d)

(c)

Grange, R et al. Nano letters 12, 2012



Nanowire radius determination Periodic SHG reponse

Distances (µm)

SH

G p

ower

(W)

576 nm

(a)

(b)

(d)

(c)

Waveguiding theory

V = (2π/λ0) r (nGaAs2- nair

2)1/2

Tong et al. Opt. Exp. 12, 1025-1035 (2004).

• Single mode condition: V ≤2.405 • For GaAs: r ≤ 89.9 nm

Radius of 78.5 ± 2 nm.



Nanowire radius determination Periodic SHG reponse

Distances (µm)

SH

G p

ower

(W)

576 nm

(a)

(b)

(d)

(c)

Periodicity of the fields 576 nm and λ0 = 820 nm

neff = 1.302

Calculated radius of 78.9 nm

AFM radius of 78.5 ± 2 nm.

No need of high resolution microscopy like SEM or AFM

Calculated radius



Periodic SHG reponse

Distances (µm)

SH

G p

ower

(W)

576 nm

(a)

(b)

(d)

(c)

Periodicity of the interferences

λeff / 2

According to waveguiding theory

λ0/neff = λeff = 576 nm

Thus more complex model needed.


Waveguiding only ? 43

Guided wave from a facet

Pol. 1

Pol. 2

Electric field

0

λ0/(2 neff) = λeff /2 Periodicity

λeff /2

SHG polarization for different phases (i.e. times)


Waveguiding and Mie scattering 44


Pol. 1

Pol. 2

Electric field

Mie scattered wave


Mie

+ =

G. Brönstrup and et al., Nanotechnology, 22(38), 2011

86 nm

102 nm

128 nm

155 nm

183 nm




Pol. 1

Pol. 2

Electric field

Mie scattered wave


Mie

+ = (n

m)

(nm)

0 λeff /2 λeff

SHG polarization for different phases (i.e. times)



Pol. 1

Pol. 2

Electric field

Mie

+ = (n

m)

(nm)

0 λeff /2 λeff

0 λeff/2 λeff


Paper & Outlook 47

Get ready for your oral presentation !

Nanomaterials and their Optical Applications · Lecture : Nanomaterials and their optical...

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