The Institute for Lasers, Photonics and Biophotonics
University at Buffalo
Emerging Opportunities
In New Directions of Photonics:
Nanophotonics and Biophotonics
P.N.Prasad
www.biophotonics.buffalo.edu

NANOPHOTONICS
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
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 and
Efficient Photovoltaic, Solar Cells
Hole transporting polymer + Inorganic semiconductor quantum 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.

InP, and InP/II-VI-Core-Shell Nanocrystals
Quantum Engineering of InP/II-VI Core-shell nanocrystals
II-VI
InP
II-VI
InP
Core/Shell nanocrystal
InP/CdS
II-VI
Core/Buffer/Shell nanocrystal
(also magnetic nanocrystals)
InP/CdSe Etched InP InP/ZnS
Etched InP nanocrystals and Core-
Shell nanocrystals (302nm excitation)

Size Tuning of Photosensitization in IR using PbSe Quantum Dots
(Dispersion in tetrachloroethylene)
2.0
1.5
1.0
0.5
0.0
600 800 1000 1200 1400 1600
Wavelength [nm]
1800 2000 2200
3.0x10
-2
2.0x10
-2
1.0x10
-2
4.0x10
-2
Photogeneration Quantum
Efficiency of PbSe Quantum Dots:
PVK nanocomposites at 1.55
µm
0.0
0 10 20 30
Applied Field, E
0
[V/
 m]
40 50

Multifunctionality in Photorefractivity:
Photoconductivity + Electro-Optic Effect
+++ +++ +++
- - - - - - -
Photogeneration of charge carriers
+++ +++ +++
- - -
- - -
- - z z
Transport of holes under the influence of external electric field
E

- - -
+++
- - -
+++ p/2
L
G z
Trapping of Space charge z
Electro-optic Index modulation

Photorefractive nanocomposite containing polymerdispersed Liquid Crystal and Quantum Dots n p n e n o
~ 200 nm Liquid Crystal Nanodroplets
~ 10 nm Quantum Dots
PMMA:ECZ:
LiquidCrystal:CdS

Photorefractive inorganic-organic polymer-dispersed liquid crystal nano-composite photosensitized with cadmium sulfide quantum dots
80
70
60
50
40
30
20
10
0
0 l
= 514.5 nm
100
PMMA:TL202:ECZ:CdS
42:40:16:2 wt.%.
Q-CdS diam. < 1.4 nm
20 40 60
Electric Field, E [V/  m]
80
Winiarz and Prasad J., Opt. Lett. (in press)

Photorefractivity for Correction of Beam Distortion
Unaberrated Aberrated Corrected
Demonstration of the ability of the PMMA:ECZ:TL202:Q-CdS composite to correct a severely aberrated image under static conditions.

Photonic crystals – A novel periodic photonic structure
0.36
0.32
0.28
0.24
0.20
0.16
0.12
0.08
0.04
0.00
-3 -2 band 2
Photonic Band Gap
-1 0
Wavevector
1 band 1
2 3
Simple band picture for a photonic crystal
3D colloidal crystal
100
80
60
40
20
0
440 460 480 500 520 540 560 580 600
Wavelength [nm]
Transmission and reflection spectra
100
80
60
40
20
0
450 500 550 600 650 700 750
Wavelength [nm]

Novel Manifestations in Photonic Crystals
1.3
1.2
1.1
1.0
0.9
0.8
0.7
0.6
0.5
0.4
0.3
0.2
0.1
0.0
X U L G X W K
Wavevector [ p /a]
Complex band structure
Superprism effect
-
Negative refraction
- Large angle deflection
- Ultradiffraction
Field enhancement
- Low threshold lasing
- Enhanced nonlinear optical effects
1.50
1.48
1.46
1.44
1.42
0.1
1560nm
0.2
520nm
0.3
0.4
0.5
0.6
Normalized frequency
0.7
Anomalous refractive index dispersion
- Control of light propogation
- Phase-matching for harmonic generation
- Self-collimation

Third-Harmonic Generation in Photonic Crystals
40 nm off
I

500 GW/cm
2

Third-Harmonic Generation in Photonic Crystals
2500
2000
1500
1000
500
0
400 450 500
Wavelength[nm]
550
Third-harmonic generation in two polystyrene PCs (d=200 & 230 nm).
0.0
600
0.6
0.4
0.2
1.0
0.8
The intensity of THG from the 1-D photonic crystal as a function of the pump wavelength.
P. Markowicz at. al., Phys. Rev. Lett. - in press.

Light Driven Nanoparticle Alignment
Use of holographic (laser) photopolymerization to induce movement and sequester nanoparticles into defined 3-dimensional patterns
Holographic Illumination Intensity interference pattern
Functional nanoparticles in reactive mixture
Sub-micron periods
(50-800 nm)
Spatially defined chemical reactivity
150 nm
Advantages: Large Scale Area, Various Geometries, Simple, and One Step Processing

1.0
Holographic polymer-dispersed liquid crystal grating.
0.9
THG
0.8
U=0V
0.8
0.6
0.4
0.2
0.0
U=160V
480 500 520 540 560 580 600
Wavelength[nm]
0.7
0.6
0.5
0.4
Transmission
0.3
480 500 520 540 560
Wavelength[nm]
580 600
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

Photonic Crystal Defect Engineering: Optical Circuitry
Two-photon fluorescence
P. Crystal
Objective
Infiltration with Resin
& 2-photon
Lithography
Grating
One-photon fluorescence
P. Crystal &
Linear Defects
1x2 Beam Splitter
(5microns below surface)

Laser Tweezers for micro- and nano- manipulation and surface adhesion
Letters composed in Liquid Crystal Multiple trapping in water by one beam
Measurement of colloidal forces and defect line tension and in liquid crystal
In collaboration with Smalyukh and Lavrentovich, ILC, Kent State University

Introduction to Biophotonics
Paras N. Prasad
(John Wiley & Sons, 2003)
SUMMARY OF CONTENTS
1.
Introduction
2.
Fundamentals of Light and Matter
3.
Basics of Biology
4.
Fundamentals of Light-Matter Interactions
5.
Principles of Lasers, Current Laser Technology, and Nonlinear Optics
6.
Photobiology
7.
Bioimaging: Principles and Techniques
8.
Bioimaging: Applications
9.
Biosensors
10. Microarray Technology for Genomics and Proteomics
11. Flow Cytometry
12. Light-Activated Therapy: Photodynamic Therapy
13. Tissue Engineering with Light
14. Laser Tweezers and Laser Scissors
15. Nanotechnology for Biophotonics: Bionanophotonics
16. Biomaterials for Photonics

Drug tracking using TPLSM
Doxorubicin
LHRH Peptide
C625
: Chemotherapy drug
: Targeting agent.
: Two-photon Chromophore

TPLSM images of MCF-7 cells showing the intake of drug into cell over a time period of 50 minutes.
l
= 800nm
Avg. Power < 15mW

=~ 90 fs f =82 MHz

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

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

FRAP : A technique to monitor protien Dynamics in Cells
FGFR1-eGFP
Pre -Bleach t
½
(s)
95% Confidence
Post -Bleach
30
20
10
0
0
40
Nucleus
53.78
50.82 to
57.10
Nuclear Membrane
76.52
71.70 to 82.03
100 200
Time (s)
300 400
Recovery
Plasma Membrane
37.63
35.55 to 39.97
Nucleus
NM
PM