Laser Group of Department of Physics

Laser Group of Department of Physics

Prof. HarshvardhanWanare

Department Day, Golden Jubilee, IIT Kanpur, March 19-20, 2010

Prof. Asima Pradhan

Prof. R. Vijaya

Prof. Raj K. Thareja

BiophotonicsLaser Plasma

Interaction

Quantum Optics

Fiber Optics, Photonic Band Gap Materials

Recent publicationsRecent publicationsRecent publicationsRecent publications

1. R.K. Thareja, A. Mohanta, D. Yadav and A. Kushwaha, (2010) Synthesis and Characterization of Nanoparticles and Nanocrystalline Functional Films, Materials Science Forum Vols. 636-637, 709-713.

2 A Mohanta and R. K. Thareja, (2009) Rayleigh scattering from gaseous phase nanoparticles synthesized by pulsed laser ablation of ZnO, J. Appl. Phys. 106, 124909.

3 Dheerendra Yadav, Varun Gupta, and Raj K Thareja (2009), Evolution and imaging of nanoparticles observed in laser ablated carbon plume, J Appl, Phys. 106, 064903.

4 Dheerendra Yadav, Varun Gupta, and Raj K Thareja, (2009) Ground state C2 density measurement in carbon

plume using Laser induced fluorescence spectroscopy, Spectra Chem ActaB 64, 986.

5 Archana Kushwaha, Antaryami Mohanta, Raj K Thareja, (2009) C2 and CN dynamics and pulsed laser

deposition of CNx films, J Appl. Phys. 105, 044902.

6 Archana Kushwaha and R K Thareja (2008) Dynamics of laser ablated carbon plasma: formation of C2 and

CN, Appl. Opt. 47, 65

7 A. Mohanta, V. Singh and Raj K Thareja (2008) Photoluminescence from ZnO nanoparticles in vapor phase, J. Appl. Phys. 104, 064903.

8 Antaryami Mohanta and Raj K Thareja (2008) Photoluminescence study of ZnO nanowires grown by thermal evaporation on pulsed laser deposited ZnO buffer layer, J. Appl. Phys. 104, 044906; Virtual J. Ultrafast Sc.

9. R. K. Thareja, A. K. Sharma, and S. Shukla (2008) Spectroscopic investigations of carious tooth decay, Med. Eng. & Phys. 30, 1143.

10. A Mohanta and R. K. Thareja, (2008) Photoluminescence study of ZnCdO alloy, J Appl Phys, 103, 024901.

Biophotonics:Application of photonic science and technology to life sciences.

A rapidly emerging area of forefront, interdisciplinary research

Requires fundamental understanding of light-biomatter interaction

Biophotonics:Application of photonic science and technology to life sciences.

A rapidly emerging area of forefront, interdisciplinary research

Requires fundamental understanding of light-biomatter interaction

For a reliable optical diagnostic tool:Require combination of more than one technique

Fluorescence Spectroscopy and Imaging(Sensitive Technique)

Elastic Scattering (Structural Information)

Raman Spectroscopy (Specific in nature)

For a reliable optical diagnostic tool:Require combination of more than one technique

Fluorescence Spectroscopy and Imaging(Sensitive Technique)

Elastic Scattering (Structural Information)

Raman Spectroscopy (Specific in nature)

Early detection of cancer :

Spectroscopy and ImagingThe basis of our research lies in extracting

molecular (fluorescence, Raman) and subtle morphological (elastic scattering) characteristics of changes in human tissue during development of disease

Early detection of cancer :

Spectroscopy and ImagingThe basis of our research lies in extracting

molecular (fluorescence, Raman) and subtle morphological (elastic scattering) characteristics of changes in human tissue during development of disease

Developed two techniques to extract authentic biochemical information from fluorescence spectra, which are modulated by wavelength dependent optical parameters

Developed two techniques to extract authentic biochemical information from fluorescence spectra, which are modulated by wavelength dependent optical parameters

Methodology used by us for extraction of Intrinsic Fluorescence

)I - GI(fl||

)I - GI(scat||

A. Polarized Fluorescence & polarized elastic scattering measurement based approach

A purely experimental approach

Normalization of polarized fluorescence by polarized elastic scattering spectra to remove the modulation of wavelength dependent optical transport parameters

A. Polarized Fluorescence & polarized elastic scattering measurement based approach

A purely experimental approach

Normalization of polarized fluorescence by polarized elastic scattering spectra to remove the modulation of wavelength dependent optical transport parameters

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0

100000

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nsity

(a.u

.)

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Measured Polarized Fluorescence

)I - GI(fl||

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)I - GI(scat||

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sity(a

.u.)

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Intinsic Fluorescence: dip removed

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Cancer Normal

NA

DH

Peak in

ten

sit

y n

orm

alised

by

Are

a o

f co

rresp

on

din

g n

orm

al

Number of Patients

Optics Express, 2003, SPIE 2010.

Fiber Jig

B. Spatially resolved fluorescence measurement

Hybrid diffusion theory, Monte Carlo based analytical model for spatially resolved fluorescence

Determination of optical transport parameters at the excitation & emission wavelengths (morphology)

Recovery of intrinsic fluorescence (biochemical)

Depth information of inhomogeneity Applied Optics 2002,2006

IMueller imaging in human cervical tissues

M11 M12 M13 M14

M21 M22 M23 M24

M31 M32 M33 M34

M41 M42 M43 M44

M11 M12 M13 M14

M21 M22 M23 M24

M31 M32 M33 M34

M41 M42 M43 M44

Emerging Stoke’s vector

S1/

S2 /

S3 /

S4 /

S1

S2

S3

S4

=

Incident Stoke’s vectorMueller Matrix

Emerging Stoke’s vector

SS2 /

S3 /

S4 /

S2 /

S3 /

S4 /

M = MΔ MR MD

DiattenuationRetardance

Depolarization

•Multiple scattering•Linear & Circularretardance

•Differential attenuation (absorption & scattering)

M = MΔ MR MD

DiattenuationRetardance

Depolarization

•Multiple scattering•Linear & Circularretardance

•Differential attenuation (absorption & scattering)

Basal layer Basal

layer

Microscope images

Normal epithelium of cervix

Dysplastic epithelium of cervix

Normal epithelium of cervix

Dysplastic epithelium of cervix

Pixel number

Pixe

l num

ber

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numb

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40µ

Depolarization power images

Fluorescence Imaging in tissues with handheld probe

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abn1 abn 2 abn 3 abn 4 abn 5 abn 6 nor 1 nor 2 nor 3 nor 4 nor 5 nor 6

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Wavelength (nm)

Cancer Normal

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NA

DH

Are

a n

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y A

rea

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Fiber locations

Polarized fluorescence spectra for normal & abnormal tissuethrough different fibers

Average fluorescence spectra of normal & abnormal tissue

NADH band area normalized by area of corresponding normal for co-polarized spectra/elastic scattering

0.22mm

7mm

4mm

2cm

B C D E F G H

1mm

Abnormal tissue Normal tissue

Raman Spectroscopy in Human Tissue

Polarized Raman Studies of Cervical Tissues

PCA & Covariance Matrix Images

-40 -30 -20 -10 0 10 20 30-15

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PC

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PC

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PC2 Vs PC3 (Co-polarized)

for cervical tissue

PC2 Vs PC3 (Un-polarized)

for cervical tissue

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Cancerous (1600 – 1700 cm-1)

Co-polarizedCo-polarized

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Normal (1300 – 1400 cm-1) Cancerous (1300 – 1400 cm-1)

Cross-polarizedCross-polarized

Co-Cross polarizedCo-Cross polarized

Future Plans

Aim towards multimodal diagnostic tool

Nano-based Imaging for contrast enhancement

Recent Publications

•JOSA A, Vol.24, #6 (2007)

• Eng. Lett ( 2007)

•Nanotechnology 18 (2007)

•Journal of Biomedical Optics (2008)• •Optics Express, Vol. 17, 1600 (2009)• •Applied Optics, Vol. 48, 6099 (2009)• •IEEE JSTQE, in press, (2010)

Current Ph.D students: 3

Current M.Tech students: 3

Funding: MCIT (DIT), CSIR

∣1 ⟩

∣3 ⟩∣2 ⟩

Multicolored Coherent Population Trapping

Sub-harmonic comb with modulated fields

New laser cooling mechanism, optical lattices, optical metrology

Quantum Optics, Metamaterials and Imaging in Random media

ω1

ω 2

Input

Output

OutputInput

Non-linear dynamics

All-optical bistability: double cavity, two-photon

• Negative-Positive Hysteresis

• Self-pulsing

• Quasi-periodic route to chaos

New paradigms of control in

metamaterials with Dispersion

All superluminal pulses become

subluminal at larger propagation

distances

Developing statistical methods

of imaging in random media

with diffuse light

Modulated

Source - ω

0o

180o

D1

D2

D3

D4

D5

Discovered fiber-based

sensor that relies on

tunneling of light

R. VijayaVisiting Professor, IIT Kanpur (since Aug 2009)Permanent position: Professor, Department of Physics, IIT Bombay

Sub-areas of research: (a) Nonlinear Fiber optics – experiment, computation, theory

Objective: To build a multi-wavelength continuous wave / short-pulse source for fiber-optic communications

b) Photonic band gap materials – experiment

Objective: To build advanced functionalities such as directional emission and lowered threshold for lasing in self-assembled photonic crystals

c) Integrated Optics - experiment

Objective: Optimization of waveguide device fabrication in newer materials

c) Computational Nonlinear Optics

Objective: Calculation of non-linear optical coefficients of nano-clusters by DFT

Present research funding > Rupees 1.0 Crore

Present group: 3 Ph.D students, 1 Project staff, 1 Post-doctoral scientist

Research on Nonlinear Fiber Optics at IIT BombayResearch Lab established during 1999-2003

Major facilities: high-power fiber amplifier, time-domain (up to GHz) and frequency-domain (near-IR) measurement facilities, fiber splicer, several fiber-optic components such as isolators, circulators, couplers etc. and specialty fibers (EDF, DSF, HNLF)

■ Tunable fiber laser ■ Options for broadband (52 nm) and multi-wavelength (64 channels) output ■ Continuous wave and mode-lcked (15 ps and 10 GHz)

output ■ Low pumping powers (< 200 mW) ■ C-band and L-band operations

R

(a) Erbium-doped fiber ring laser tunable from 1560 to 1605 nm by intra-cavity loss

(b) Broadband generation using intra-cavity four-wave mixing in a low-dispersion fiber

(c) Active mode-locking at 10 GHz - economical design based on Gunn oscillator

(a) (b) (c)

Research on Photonic band gap materials at IIT BombayResearch Lab established during 2004-2007

Major facilities: Thin film spin coater, film thickness measurement system, lamp - monochromator - detector for 200nm to 2000 nm, pulsed Nd:YAG laser, waveguide coupling set-up and m-line set-up.

■ 3-D photonic crystals by self-assembly ■ characterization ■ Tuning of stop band ■ Inverse crystals ■ Photonic crystal heterostructures ■ Direction-dependent emission ■ Spectral narrowing ■ Photonic crystal waveguides

Double stop band Directional emission

Telecom band Large area crystal; Stop band at 550nm Waveguide by EBL Light guidance

Self-assembled crystal

Future scope of studies

• Nonlinear dynamical effects in fiber lasers for Secure Communications

• Slow light characteristics in optical fibers• Photonic crystal antenna – design issues• Band-edge nonlinearities in Photonic crystals

1. J. Appl. Phys. 104, 053104 (2008)2. Appl. Phys. A, 90, 559 (2008)3. J. Non. Opt. Phys and Mater. 18, 85 (2009)4. Applied Optics 48, G28 (2009)5. Prog. Quant. Electr. (in press)

Recent publications