Transcript Document 7345795

Laser Group of Department of
Physics
Prof. Raj K. Thareja
Prof. HarshvardhanWanare
Prof. Asima Pradhan
Laser Plasma
Interaction
Biophotonics
Quantum
Optics
Fiber Optics,
Photonic Band
Gap Materials
Prof. R. Vijaya
Department Day,
Golden Jubilee, IIT Kanpur,
March 19-20, 2010
Recent 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
technology to life sciences.
Early detection of cancer :
science
and
A rapidly emerging area of forefront,
interdisciplinary research
Requires fundamental understanding of
light-biomatter interaction
Spectroscopy and Imaging
The 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
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)
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
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
12000000
Intensity(a.u.)
300000
( I || - G  I  )
200000
fl
10000000
1.4
Measured Elastic
Scattering
Intensity(a.u.)
Measured Polarized
Fluorescence
400000
intensity(a.u.)
500000
8000000
6000000
4000000
( I || - G  I  )
100000
2000000
scat
1.2
Intinsic Fluorescence:
dip removed
1.0
0.8
0.6
0.4
0.2
0.0
0
0
350
400
450
 (nm)
( I || - G  I  )
500
550
600
650
350
400
450
500
550
600
650
-0.2
350
400
450
500
550
600
 (nm)
 (nm)
fl
B. Spatially resolved fluorescence measurement
Fiber Jig
Hybrid diffusion theory, Monte Carlo based analytical
( I || - G  I  )
scat
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
650
NADH Peak intensity normalised by
Area of corresponding normal
Cancer
Normal
1.6
0.1
0.01
0
5
10
15
20
25
30
35
40
45
Number of Patients
Optics Express, 2003,
SPIE 2010.
B C D E
F G
Raman Spectroscopy
in Human Tissue
IMueller imaging in
human cervical tissues
Fluorescence Imaging in tissues
with handheld probe
S1/
S2/
S3/
S4/
H
=
M11
M12
M13
M14
M21
M22
M23
M24
M31
M32
M33
M34
M41
M42
M43
M44
S1
S2
S3
S4
Polarized Raman Studies of Cervical Tissues
7mm
Emerging Stoke’s
vector
Mueller Matrix
1mm
Incident
Stoke’s vector
PCA & Covariance Matrix Images
M = MΔ MR MD
0.22mm
2cm
15
15
10
10
5
5
Diattenuation
Depolarization
PC3
PC3
0
-5
-10
Retardance
0
-5
-15
-10
-20
-15
-40
abn1
abn 2
abn 3
abn 4
abn 5
abn 6
nor 1
nor 2
nor 3
nor 4
nor 5
nor 6
2400
2200
2000
Intensity
1800
1600
1400
1200
1000
•Multiple scattering
Cancer
Normal
1000
Pixel number
400
200
200
0
450
500
550
600
650
0
350
700
400
Wavelength (nm)
450
500
550
600
650
700
Wavelength (nm)
Polarized fluorescence spectra
for normal & abnormal tissue
through different fibers
25
0.7
20
0.6
Average fluorescence spectra of
normal & abnormal tissue
0.5
15
Normal
epithelium10
of cervix
0.4
0.3
40
Pixel number
NADH Area normalised by
Area of corresponding normal
0.35
0.30
Normal
epithelium
of cervix
0.20
0.15
50
100
150
200
250
Fiber locations
NADH band area normalized by area of corresponding
normal for co-polarized spectra/elastic scattering
0.7
20
0.6
0.5 Dysplastic
15
0.4
10
-10
0
-30
-20
-10
0
10
20
30
PC2
10
PC2 Vs PC3 (Co-polarized)
for cervical tissue
for cervical tissue
Cross-polarized
4
0
µ
60
epithelium
of cervix
20
20
40
40
60
60
80
80
100
100
60
80
100
120
140
40
60
80
100
120
140
120
140
140
Normal (1600 –
1700 cm-1)
160
40
60
80
100
120
140
160
20
40
60
80
100
Cancerous (1600 –
1700 cm-1)
Normal
(1600 –
1700 cm1)
Cancerous
(1600 –
1700 cm-1)
Co-Cross polarized
20
20
40
40
Dysplastic
epithelium
of cervix
60
60
80
80
100
100
120
120
140
140
160
160
180
200
220
220
20
40
60
80
100
120
140
160
180
200
Normal (1300 – 1400
120
160
200
Microscope images
80
100
120
20
20
160
80
Basal
layer
60
100
160
160
40
180
Basal
layer
40
80
140
140
20
0.2
20
40
120
120
160
4
20
40
60
80
Pixel number
Depolarization power
images
0
µ
20
60
0.3
0.2
20
Normal
Cancer
0.25
25
5
5
0.40
0
-20
PC2
Co-polarized
600
400
•Differential attenuation
(absorption & scattering)
-30
600
400
800
350
•Linear & Circular
retardance
-40
PC2 Vs PC3 (Un-polarized)
800
Intensity
2600
-25
-50
Normal tissue
4mm
Pixel number
Abnormal tissue
220
cm-1)
20
40
60
80
100
120
140
160
180
200
220
Cancerous (1300 – 1400 cm-1)
140
160
Future Plans
Recent Publications
Aim towards multimodal diagnostic
tool
•JOSA A, Vol.24, #6 (2007)
Nano-based Imaging for contrast
enhancement
• Eng. Lett ( 2007)
•Nanotechnology 18 (2007)
Current Ph.D students: 3
Current M.Tech students: 3
Funding: MCIT (DIT), CSIR
•Journal of Biomedical Optics (2008)
•
•Optics Express, Vol. 17, 1600 (2009)
•
•Applied Optics, Vol. 48, 6099 (2009)
•
•IEEE JSTQE, in press, (2010)
Quantum Optics, Metamaterials and Imaging in Random media
All-optical bistability: double cavity, two-photon
ω2
Output
Non-linear dynamics
Input
Input
Output
ω1
• Negative-Positive Hysteresis
• Self-pulsing
∣1〉
• Quasi-periodic route to chaos
Multicolored Coherent Population Trapping
Sub-harmonic comb with modulated fields
∣2〉
∣3〉
New laser cooling mechanism, optical lattices, optical metrology
New paradigms of control in
metamaterials with Dispersion
All superluminal pulses become
subluminal at larger propagation
distances
Modulated
Source - ω
Developing statistical methods
of imaging in random media
with diffuse light
D1
D2
D3
0o
180o
D4
D5
Discovered fiber-based
sensor that relies on
tunneling of light
R. Vijaya
Visiting Professor, IIT Kanpur (since Aug 2009)
Permanent position: Professor, Department of Physics, IIT Bombay
Sub-areas of research:
(a)
b)
c)
c)
Nonlinear Fiber optics – experiment, computation, theory
Objective: To build a multi-wavelength continuous wave / short-pulse
source for fiber-optic communications
Photonic band gap materials – experiment
Objective: To build advanced functionalities such as directional
emission and lowered threshold for lasing in self-assembled photonic
crystals
Integrated Optics - experiment
Objective: Optimization of waveguide device fabrication in newer
materials
Computational Nonlinear Optics
Objective: Calculation of non-linear optical coefficients of nanoclusters 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 Bombay
Research 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)
R
(a)
(b)
(c)
(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
■ 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
Research on Photonic band gap materials at IIT Bombay
Research 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.
Self-assembled crystal
Telecom band
Double stop band
Large area crystal; Stop band at 550nm
Directional emission
Waveguide by EBL
Light guidance
■ 3-D photonic crystals by self-assembly ■ characterization ■ Tuning of stop
band ■ Inverse crystals ■ Photonic crystal heterostructures ■ Directiondependent emission ■ Spectral narrowing ■ Photonic crystal waveguides
Recent publications
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)
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