“Lighting the Way to Technology through Innovation”

The Institute for Lasers, Photonics and Biophotonics

University at Buffalo

Emerging Opportunities

In New Directions of Photonics:

Nanophotonics and Biophotonics

P.N.Prasadwww.biophotonics.buffalo.eduwww.biophotonics.buffalo.edu

Nanoscale Optical Interaction and Dynamics:

Nonradiative Processes for Photonic Functions/Dynamics <10 nm

Optically Induced Photonics Functions/Dynamics sub wavelengths

Manifestations:

Size Dependent Optical Transitions

Novel Optical Resonances

Nano-control of Excitations Dynamics

Manipulation of Light Propagation

Nanoscopic Field Enhancement

NANOPHOTONICS

NANOPHOTONICS Paras N. Prasad

(John Wiley & Sons, April 2004)

SUMMARY OF CONTENTS

1. Introduction 2. Foundations for Nanophotonics 3. Near Field Interaction and Microscopy 4. Quantum Confined Materials 5. Plasmonics 6. Nanocontrol of Excitation Dynamics 7. Processing and Characterization of Nanomaterials 8. Nanostructured Molecular Architectures 9. Nanocomposites 10. Photonic Crystals 11. Nanolithography 12. Biomaterials for Nanophotonics 13. Nanophotonics for Biotechnology and Nanomedicine 14. The Market Place for Nanophotonics

Nanocomposites for Broad Band andEfficient Photovoltaic, Solar Cells

Hole transporting polymer + Inorganic semiconductorquantum dots

Features:

• In corporation of quantum dots to produce a direct junction between the polymer and the quantum dots.

• Efficient photosensitization over a broad wavelength covering from UV to IR by choice of the size and type of inorganic

semiconductor nanocrystals ... efficient solar harvesting.

• Enhanced carrier mobility for improved collection efficiency.

Quantum Engineering of InP/II-VI Core-shell nanocrystals

Etched InP nanocrystals and Core-Shell nanocrystals (302nm excitation)

InP, and InP/II-VI-Core-Shell Nanocrystals

Core/Shell nanocrystal

InP

II-VI

Core/Buffer/Shell nanocrystal(also magnetic nanocrystals)

InP

II-VI

II-VI

InP/CdS InP/CdSe Etched InP InP/ZnS

600 800 1000 1200 1400 1600 1800 2000 2200

0.0

0.5

1.0

1.5

2.0

Ab

sorb

an

ce [a

.u.]

Wavelength [nm]

0 10 20 30 40 50

0.0

1.0x10-2

2.0x10-2

3.0x10-2

4.0x10-2

Pho

toge

ner

atio

n Q

E,

[%]

Applied Field, E0 [V/m]

Size Tuning of Photosensitization in IR using PbSe Quantum Dots

(Dispersion in tetrachloroethylene)

Photogeneration Quantum Efficiency of PbSe Quantum Dots: PVK nanocomposites at 1.55µm

Transport of holes under the influence of external electric field

Photogeneration of charge carriers

Trapping of Space charge

Electro-optic Index modulation

z

+++ +++ +++- - -- - - - - -

+++ +++ +++- - - - - -- - -

- - -+++

- - -

+++

G

z

z

z

E

Multifunctionality in Photorefractivity:Multifunctionality in Photorefractivity: Photoconductivity + Electro-Optic Effect

~ 200 nm Liquid Crystal Nanodroplets

np no

ne ~ 10 nm Quantum Dots

PMMA:ECZ:LiquidCrystal:CdS

Photorefractive nanocomposite containing polymer-dispersed Liquid Crystal and Quantum Dots

Photorefractive inorganic-organic polymer-dispersed liquid crystal nano-composite photosensitized with

cadmium sulfide quantum dots

0 20 40 60 80 100

0

10

20

30

40

50

60

70

80

Diff

ract

ion

Eff

icie

ncy

, [%

]

Electric Field, E [V/m]

PMMA:TL202:ECZ:CdS 42:40:16:2 wt.%.

Q-CdS diam. < 1.4 nm = 514.5 nm

Winiarz and Prasad J., Opt. Lett. (in press)

Unaberrated Aberrated Corrected

Demonstration of the ability of the PMMA:ECZ:TL202:Q-CdS composite to correct a severely aberrated image under static conditions.

Photorefractivity for Correction of Beam Distortion

-3 -2 -1 0 1 2 30.00

0.04

0.08

0.12

0.16

0.20

0.24

0.28

0.32

0.36

band 2

band 1

Photonic Band Gap

Fre

quen

cy

Wavevector

Simple band picture for a photonic crystal

440 460 480 500 520 540 560 580 6000

20

40

60

80

100

Tra

nsm

ittan

ce [%

]

Wavelength [nm]

Transmission and reflection spectra

450 500 550 600 650 700 7500

20

40

60

80

100

Ref

lect

ance

[%]

Wavelength [nm]

3D colloidal crystal

Photonic crystals – A novel periodic photonic structure

0.0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1.0

1.1

1.2

1.3

X U L X W K

No

rma

lize

d f

req

ue

ncy

Wavevector [/a]

0.1 0.2 0.3 0.4 0.5 0.6 0.7

1.42

1.44

1.46

1.48

1.50

520nm1560nmE

ffective

refr

active

index

Normalized frequency

Novel Manifestations in Photonic Crystals

Complex band structure

Field enhancement- Low threshold lasing- Enhanced nonlinear optical effects

Superprism effect- Negative refraction- Large angle deflection- Ultradiffraction

Anomalous refractive index dispersion- Control of light propogation- Phase-matching for harmonic generation- Self-collimation

Third-Harmonic Generation in Photonic Crystals

2GW/cm 500I

40 nm off

Third-Harmonic Generation in Photonic Crystals

400 450 500 550 6000

500

1000

1500

2000

2500

Tra

nsm

ittan

ce

TH

G I

nten

sity

[a.

u.]

Wavelength[nm]

0.0

0.2

0.4

0.6

0.8

1.0

Third-harmonic generation in two polystyrene PCs (d=200 & 230 nm).

P. Markowicz at. al., Phys. Rev. Lett. - in press.

The intensity of THG from the 1-D photonic crystal as a function of the pump wavelength.

Advantages: Large Scale Area, Various Geometries, Simple, and One Step Processing

150 nm

Use of holographic (laser) photopolymerization to induce movement and sequester nanoparticles into defined 3-dimensional patterns

Holographic Illumination Intensity interference pattern

Sub-micron periods (50-800 nm)

Functional nanoparticles in reactive mixture

Spatially defined chemical reactivity

Light Driven Nanoparticle Alignment

Electrically Switchable Photonic Crystal

480 500 520 540 560 580 600

0.0

0.2

0.4

0.6

0.8

1.0

U=160V

U=0V

TH

Inte

nsity

[a. u

.]

Wavelength[nm]

480 500 520 540 560 580 600

0.3

0.4

0.5

0.6

0.7

0.8

0.9

Transmission

THG

Inte

nsity

[a. u

.]Wavelength[nm]

Holographic polymer-dispersed liquid crystal grating.

The intensity of THG from the 1-D photonic crystal as a function of the applied voltage.

The transmission spectrum of the crystal & the third-harmonic signal.

In collaboration with AFRL, Dayton

Two-photon Lithography using femtosecond pulses

P. Crystal

Infiltration with Resin & 2-photon Lithography

P. Crystal & Linear Defects

Objective

1x2 Beam Splitter(5microns below surface)

Grating

Two-photon fluorescence

Photonic Crystal Defect Engineering: Optical Circuitry

One-photon fluorescence

In collaboration with Smalyukh and Lavrentovich, ILC, Kent State University

Laser Tweezers for micro- and nano- manipulation and surface adhesion

Multiple trapping in water by one beamLetters composed in Liquid Crystal

Measurement of colloidal forces and defect line tension and in liquid crystal

Introduction to Biophotonics Paras N. Prasad

(John Wiley & Sons, 2003)

SUMMARY OF CONTENTS 1. Introduction2. Fundamentals of Light and Matter3. Basics of Biology4. Fundamentals of Light-Matter Interactions5. Principles of Lasers, Current Laser Technology, and Nonlinear Optics6. Photobiology7. Bioimaging: Principles and Techniques8. Bioimaging: Applications9. Biosensors10. Microarray Technology for Genomics and Proteomics11. Flow Cytometry12. Light-Activated Therapy: Photodynamic Therapy13. Tissue Engineering with Light14. Laser Tweezers and Laser Scissors15. Nanotechnology for Biophotonics: Bionanophotonics16. Biomaterials for Photonics

Drug tracking using TPLSM

Doxorubicin : Chemotherapy drug

LHRH Peptide : Targeting agent.

C625 : Two-photon Chromophore

TPLSM images of MCF-7 cells showing the intake of drug into cell over a time period of 50 minutes.

= 800nmAvg. Power < 15mW=~ 90 fsf =82 MHz

Confocal images of MCF 7 cells. The arrows indicate The location where the spectra were taken.

Nucleus

Membrane

Cytoplasm

LHTPR

AC

Spectra profiles of AC&LHTPR treated MCF-7 cell (inside the Nucleus, Cytoplasm and on the Membrane)

Localized spectroscopy was used to identify the localization of a chemotherapeutic drug and and one of its component, the carrier protein, inside human cancer cells.

The ratio between the two emission at ~490nm (From AN152:C625) and the Emission at ~590 (From LHRH:TPR) was studied in different cell lines as well as in different parts of a cell to understand the roll of LHRH in carrying the drug into the cells.

Excitation Source: Ti:Sapphire laser tuned to a center wavelength of 800nm.

FGFR1-eGFP

Pre -Bleach Post -Bleach Recovery

0 100 200 300 400

0

10

20

30

40Nucleus

NM

PM

Time (s)

Flu

ore

sce

nc

e R

ec

ov

ery

(%

)

35.55 to 39.9771.70 to 82.0350.82 to

57.10

95% Confidence

37.6376.5253.78t½

(s)

Plasma MembraneNuclear MembraneNucleus

FRAP : A technique to monitor protien Dynamics in Cells