Laser Group of Department of Physics Prof. HarshvardhanWanare Department Day, Golden Jubilee, IIT...
-
Upload
amanda-owensby -
Category
Documents
-
view
214 -
download
0
Transcript of Laser Group of Department of Physics Prof. HarshvardhanWanare Department Day, Golden Jubilee, IIT...
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
350 400 450 500 550 600 650
0
100000
200000
300000
400000
500000
Inte
nsity
(a.u
.)
(nm)
Measured Polarized Fluorescence
)I - GI(fl||
350 400 450 500 550 600 650
0
2000000
4000000
6000000
8000000
10000000
12000000
inte
nsity
(a.u
.) (nm)
Measured Elastic Scattering
)I - GI(scat||
350 400 450 500 550 600 650-0.2
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
1.6
Inten
sity(a
.u.)
(nm)
Intinsic Fluorescence: dip removed
0 5 10 15 20 25 30 35 40 45
0.01
0.1
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
20 40 60 80
5
10
15
20
25
0.2
0.3
0.4
0.5
0.6
0.7
Pixel number
Pixel
numb
er
20 40 60 80
5
10
15
20
25
0.2
0.3
0.4
0.5
0.6
0.7
40µ
40µ
Depolarization power images
Fluorescence Imaging in tissues with handheld probe
350 400 450 500 550 600 650 700
0
200
400
600
800
1000
1200
1400
1600
1800
2000
2200
2400
2600
Inte
ns
ity
Wavelength (nm)
abn1 abn 2 abn 3 abn 4 abn 5 abn 6 nor 1 nor 2 nor 3 nor 4 nor 5 nor 6
350 400 450 500 550 600 650 7000
200
400
600
800
1000
Inte
nsi
ty
Wavelength (nm)
Cancer Normal
0 50 100 150 200 250
0.15
0.20
0.25
0.30
0.35
0.40
Normal Cancer
NA
DH
Are
a n
orm
alis
ed b
y A
rea
of
corr
esp
on
din
g n
orm
al
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
-10
-5
0
5
10
15
PC2
PC
3
-50 -40 -30 -20 -10 0 10-25
-20
-15
-10
-5
0
5
10
15
PC2
PC
3
PC2 Vs PC3 (Co-polarized)
for cervical tissue
PC2 Vs PC3 (Un-polarized)
for cervical tissue
20 40 60 80 100 120 140 160
20
40
60
80
100
120
140
160
20 40 60 80 100 120 140 160
20
40
60
80
100
120
140
160
Normal (1600 – 1700 cm-1)
Cancerous (1600 – 1700 cm-1)
Co-polarizedCo-polarized
20 40 60 80 100 120 140 160
20
40
60
80
100
120
140
160
20 40 60 80 100 120 140 160
20
40
60
80
100
120
140
160
Normal (1600 –
1700 cm-
1)
Cancerous (1600 –
1700 cm-1)
20 40 60 80 100 120 140 160 180 200 220
20
40
60
80
100
120
140
160
180
200
22020 40 60 80 100 120 140 160 180 200 220
20
40
60
80
100
120
140
160
180
200
220
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