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					                   Laser Group of Department of
                             Physics


    Prof. Raj K. Thareja                                   Prof. Asima Pradhan
                           Laser Plasma    Biophotonics
                            Interaction



                                           Fiber Optics,
                            Quantum
                                          Photonic Band
Prof. HarshvardhanWanare     Optics                          Prof. R. Vijaya
                                          Gap Materials




                                                           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:                                  Early detection of cancer :
Application of photonic       science   and
                                               Spectroscopy and Imaging
technology to life sciences.
                                               The basis of our research lies in extracting
A rapidly emerging area of forefront,         molecular (fluorescence, Raman) and subtle
interdisciplinary research                     morphological (elastic scattering) characteristics
                                               of changes in human tissue during
Requires fundamental understanding of
                                               development of disease
light-biomatter interaction




For a reliable optical diagnostic tool:
Require combination of more than one           Developed two techniques to extract
technique                                       authentic biochemical information
Fluorescence Spectroscopy and Imaging          from fluorescence spectra, which are
                   (Sensitive Technique)        modulated by wavelength dependent
Elastic Scattering (Structural Information)    optical parameters
Raman Spectroscopy (Specific in nature)
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

                                                                                                                                                                                                                                                                                                                                              Cancer
                                                                                                                                                                                                                                                                                                                                              Normal
                                                                                                                                                                                                      1.6




                                                                                                                                                                                                                                                       NADH Peak intensity normalised by
                                                                                                                       12000000




                                                                                                                                                                                                                                                         Area of corresponding normal
                                              500000                                                                                                                                                  1.4
                                                                                                                                    Measured Elastic




                                                                                                                                                                                    Intensity(a.u.)
                                                                       Measured Polarized                              10000000
                                                                                                                                     Scattering                                                       1.2                                                                                   0.1




                                                                                                     intensity(a.u.)
                                              400000
                                                                        Fluorescence                                                                                                                  1.0
                                                                                                                                                                                                                             Intinsic Fluorescence:
                                                                                                                       8000000
                                              300000                                                                                                                                                  0.8
                                                                                                                                                                                                                              dip removed
                            Intensity(a.u.)




                                                                           ( I || - G  I  )                          6000000
                                              200000                                            fl                                                                                                    0.6

                                                                                                                       4000000
                                                                                                                                                    ( I || - G  I  )
                                                                                                                                                                                                      0.4
                                                                                                                                                                                                                                                                                           0.01
                                              100000
                                                                                                                       2000000
                                                                                                                                                                         scat                         0.2


                                                  0
                                                                                                                                                                                                      0.0
                                                                                                                             0                                                                                                                                                                    0   5   10    15   20   25   30   35   40   45
                                                                                                                                                                                                      -0.2
                                                   350   400   450   500     550   600   650                                                                                                              350   400   450      500   550   600   650
                                                                                                                                                                                                                                                                                                               Number of Patients
                                                                                                                              350   400   450     500    550   600   650
                                                           (nm)
                                                                                                                                                 (nm)                                                                       (nm)                                                                              Optics Express, 2003,
                                                                                                                                                                                                                                                                                                                     SPIE 2010.


  ( I || - G  I  )
                       fl

                  B. Spatially resolved fluorescence measurement
                       Hybrid diffusion theory, Monte Carlo based analytical
                                          ( I || - G  I  )
                       model for spatially resolved fluorescence
                                                             scat
Fiber Jig

                       Determination of optical transport parameters at the
                       excitation & emission wavelengths (morphology)
                       Recovery of intrinsic fluorescence (biochemical)
                       Depth information of inhomogeneity                                                                                                                       Applied Optics 2002,2006
Fluorescence Imaging in tissues                                                                                                                                                                                     IMueller imaging in                                                                                                                      Raman Spectroscopy
     with handheld probe                                                                                                                                                                                           human cervical tissues                                                                                                                     in Human Tissue




                                                                                                                                                                                                                   S1/                               M11             M12                  M13           M14
                                                                                                                                                                                                                                                                                                                         S1
                                                                                                                                                                                                                   S2/                               M21             M22                  M23            M24                                             Polarized Raman Studies of Cervical Tissues
                                                                                                                                                                                                                                                                                                                         S2
                                                                                                                                                                                                                   S3/             =                 M31             M32                  M33            M34
                                                                                                                                                                                                                                                                                                                         S3
                                                                                          B C D E             F G                  H                                                                                                                 M41             M42                  M43            M44
                                                                                                                                                                                                                   S4/                                                                                                   S4
                                                                                                       7mm

                                                                                                       1mm                                                                                      Emerging Stoke’s                                                                                                        Incident
                                                                                                                                                                                                  vector         Mueller Matrix                                                                                       Stoke’s vector
                                                                                                                                                                                                                                                                                                                                                                                              PCA & Covariance Matrix Images
                                    2cm                                                                                                                    0.22mm                                                                                     M = MΔ MR MD                                                                                     15                                                                                                                                                   15


                                                                                                                                                                                                                                                                                                                                                       10
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            10

                                                                                                                                                                                                                                                                                                                                                        5
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             5
                                                                                                                                                                                                                                                                                                                                                        0




                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                      PC3
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             0




                                                                                                                                                                                                                                                                                                                                                 PC3
                                                                                                                                                                                                                                                                                                                                                        -5




                                                                                                                                                                                                                                   Depolarization                                          Diattenuation                                               -10                                                                                                                                                   -5




                                                                                                                                                                                                                                                             Retardance                                                                                -15


                                                                                                                                                                                                                                                                                                                                                       -20
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            -10



                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            -15
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              -40            -30         -20          -10                  0                 10                 20              30
                                                                                                                                                                                                                                                                                                                                                       -25                                                                                                                                                                                                    PC2
                                                                                                                                                                                                                                                                                                                                                         -50               -40                          -30                        -20                 -10                       0               10

                             Abnormal tissue                                                           4mm                                       Normal tissue                                                                                                                                                                                                                                                                     PC2



                                                                                                                                                                                                                                                                                                                                                                    PC2 Vs PC3 (Un-polarized)                                                                                                                           PC2 Vs PC3 (Co-polarized)
             2600                                                                              abn1                                                                                                                    •Multiple scattering                                               •Differential attenuation                                                                                                                                                                                                     for cervical tissue
             2400
                                                                                               abn 2
                                                                                               abn 3
                                                                                                                            1000                                                 Cancer
                                                                                                                                                                                 Normal
                                                                                                                                                                                                                                                       •Linear & Circular                 (absorption & scattering)                                                 for cervical tissue
             2200                                                                              abn 4
             2000                                                                              abn 5                                                                                                                                                   retardance
                                                                                                                            800
             1800                                                                              abn 6                                                                                                                                                                                                                                                                                    Co-polarized                                                                                                                                                  Cross-polarized
                                                                                               nor 1
             1600
                                                                                                                Intensity




                                                                                               nor 2
 Intensity




             1400                                                                              nor 3                        600
                                                                                               nor 4
             1200
             1000
                                                                                               nor 5                                                                                                              25                                           0.7                   25                                 0.7                20                                                                                20
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  20                                                                   20


                                                                                               nor 6                        400
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  40                                                                   40

             800                                                                                                                                                                                                                                                                                                                           40                                                                                40

                                                                                                                                                                                                                                                                                                                        0.6
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  60                                                                   60

                                                                                                                                                                                                                  20                                           0.6
                                                                                                                                                                                                                                                                      Pixel number




             600
                                                                                                                                                                                                                                                                                     20                                                    60                                                                                60
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  80                                                                   80
                                                                                                                                                                                                   Pixel number




             400                                                                                                            200                                                                                                                                                                                                            80                                                                                80


                                                                                                                                                                                                                                                                                                                        0.5 Dysplastic
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  100                                                                  100

             200                                                                                                                                                                                                                                               0.5                                                                         100                                                                               100


               0
                                                                                                                                                                                                                  15                                                                 15                                       epithelium   120                                                                               120
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  120                                                                  120


                                                                                                                              0                                                             Normal                                                                                                                                                                                                                                                                                                                140                                                                  140

                350    400   450      500   550                              600         650     700                           350       400      450      500   550      600   650   700                                                                      0.4                                                      0.4   of cervix    140                                                                               140
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  160                                                                  160

                                   Wavelength (nm)                                                                                                      Wavelength (nm)
                                                                                                                                                                                            epithelium10                                                                             10                                                    160                                                                               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                          20     40     60         80     100   120       140   160

                                                                                                                                                                                            of cervix
  Polarized fluorescence spectra                                                                               Average fluorescence spectra of                                                                                                                 0.3                                                      0.3
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         Normal                                                          Cancerous
                                                                                                                                                                                                                  5                                                                  5                                                     Normal (1600 –                                                                            Cancerous (1600 –
   for normal & abnormal tissue                                                                                normal & abnormal tissue                                                                                                                        0.2                                                      0.2                  1700 cm-1)                                                                                 1700 cm-1)                                                                                        (1600 –                                                         (1600 –
  through different fibers                                                                                                               Normal
                                                                                                                                         Cancer
                                                                                                                                                                                                                            20       40
                                                                                                                                                                                                                                 Pixel number
                                                                                                                                                                                                                                                60      4
                                                                                                                                                                                                                                                       80            20      40      60 80
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         1700 cm-
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             1)
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         1700 cm-1)

                                                                                                                                                                                                                                                     Depolarization power images
                                                                                                                                                                                                                                                                        Pixel number
                                                                                                                                                                                                                                                        0
                                                                              0.40
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                           Co-Cross polarized
                                              Area of corresponding normal




                                                                              0.35
                                               NADH Area normalised by




                                                                                                                                                                                                                                                                                                                                                                                       20                                                                                                                                                 20


                                                                              0.30



                                                                              0.25
                                                                                                                                                                                            Normal
                                                                                                                                                                                                                                                        µ                                                                     Dysplastic
                                                                                                                                                                                                                                                                                                                              epithelium
                                                                                                                                                                                                                                                                                                                                                                                       40

                                                                                                                                                                                                                                                                                                                                                                                       60

                                                                                                                                                                                                                                                                                                                                                                                       80

                                                                                                                                                                                                                                                                                                                                                                                       100

                                                                                                                                                                                                                                                                                                                                                                                       120
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          40

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          60

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          80

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          100

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          120

                                                                                                                                                                                            epithelium                                                                                                                        of cervix
                                                                                                                                                                                                                                                                                                                                                                                       140                                                                                                                                                140

                                                                                                                                                                                                                                                                                                                                                                                       160                                                                                                                                                160

                                                                              0.20                                                                                                          of cervix                                                                                                                                                                                  180                                                                                                                                                180




                                                                              0.15                                                                                                          4                                     Basal
                                                                                                                                                                                                                                                                                                 Basal
                                                                                                                                                                                                                                                                                                                                                                                       200

                                                                                                                                                                                                                                                                                                                                                                                       220
                                                                                                                                                                                                                                                                                                                                                                                                   20         40   60   80     100   120   140   160    180    200   220
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          200

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                          220
                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                20    40     60     80   100   120   140     160   180   200    220




                                                                                     0          50     100      150                200     250
                                                                                                                                                                                                                                  layer                                                                                                                                   Normal (1300 – 1400                                                                        cm-1)                                                   Cancerous (1300 – 1400 cm-1)

                      NADH band area normalized by area of corresponding
                                                                                                        Fiber locations
                                                                                                                                                                                            0                                                                                                    layer


                      normal for co-polarized spectra/elastic scattering                                                                                                                    µ                                                               Microscope images
Future Plans                             Recent Publications

Aim towards multimodal diagnostic
tool                                •JOSA A, Vol.24, #6 (2007)

 Nano-based Imaging for contrast    • Eng. Lett ( 2007)
enhancement
                                    •Nanotechnology 18 (2007)

                                    •Journal of Biomedical Optics (2008)
 Current Ph.D students: 3           •
 Current M.Tech students: 3         •Optics Express, Vol. 17, 1600 (2009)
                                    •
                                    •Applied Optics, Vol. 48, 6099 (2009)
                                    •
                                    •IEEE JSTQE, in press, (2010)
  Funding: MCIT (DIT), CSIR
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
                                                  ∣2〉
Sub-harmonic comb with modulated fields
                                                            ∣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
                                 D1
with diffuse light
                                 D2                 0o

                                 D3                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)   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 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          Double stop band                 Directional emission




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

				
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