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.  Structured beams such as Laguerre Gauss (LG), Bessel beams and other dark-core beams are of special interest in recent years.


Recent activities also include quantum imaging and sensing and interplay of femtosecond-pulses using noncollinear optical parametric amplification, pump-probe techniques, pulse characterisation using the techniques of autocorrelation, frequency resolved optical gating (FROG) and spectral phase interferometry for direct reconstruction of the electric field (SPIDER).


Low dimensional materials (such as graphene, HBN, MoS2, WS2 and metal nanoparticles) and newly synthesised organic dipole/octupolar systems with the properties of Saturable absorption and Multiphoton absorption are target systems.

Fair amount of activity runs on Whispering Gallery Modes (WGMs)of a cavity. A recent patent using photonic nanojet (PNJ) is another area on Raman enhancement. Overall, the focus of  the research work is the training of the future generation!



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, Quantum correlated twin beams

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

8. Generation and application of  Structured beams such as Laguerre Gauss (LG), Bessel beams

9. Quantum imaging and sensing


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