Ultrafast Lasers and Optical Amplifiers
Physics department, IIT Madras, Chennai 600 036, India

Following are our Research Interests:

 

We investigate the ultrafast dynamics of a short-lived entity –“The excited state”.

We use the techniques of steady-state and time-resolved luminescence microscopy, confocal microscopy, laser induced transient grating, multiphoton excitation spectroscopy as well as continuous wave (cw) and ps z-scan.

 

Recent activities also include femtosecond pulse generation using noncollinear optical parametric amplification, their characterisation using the techniques of autocorrelation, frequency resolved optical gating (FROG) and spectral phase interferometry for direct reconstruction of the electric field (SPIDER).

 

New materials (such as graphene and metal nanoparticles) and newly synthesised organic dipole/octupole systems with the properties of Saturable absorption and Multiphoton absorption are target systems.


Whispering Gallery Modes (WGMs) are indispensable and we have exploited these in microspheres for basic research, besides for a recent patent on Raman enhancement.

 

Fluorescence from a dye embedded microcavity

Laser induced transient grating

 


White light continuumin water  with 35 ps duration pulses

NOPA activity

 

 

1. Morphology dependent resonances (MDRs) or Whispering Gallery Modes (WGMs) and control of radiative rate from single particle fluorescence.

2. Forster energy transfer and energy migration-effect of microcavity WGMs

3. Plasmonics and sensors

4. Multiphoton excitation and lasing in newly synthesized dyes (in collaboration with the Chemistry department)

5. Laser induced transient grating and relaxation processes in dyes, carbon nanomaterials and metal nanoparticles

6. White light continuum generation, and Optical parametric amplifiers

7. Determination of third order optical nonlinearity and excited-state & multiphoton absorption cross sections.

 

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