Intense light-matter interaction has been a topic of significant interest for several decades. Femtosecond pulsed lasers1 have been the stepping stone for transcending the weak perturbation regime of nonlinear optics and entering into the strong light-matter interaction and quantum regime of attosecond science. With these emerging areas of interest along with the development of nano-science and nanotechnology to high precision manipulation and engineering, intense light interaction has become a rapidly expanding field of research. The major objective of this work is based on understanding of nonlinear light-matter interactions in different systems. In particular, it involves nonlinear interactions in gas filled fibers with applications in few-cycle pulse generation, wavemixing in highly nonlinear liquids and collective dynamics of excitons in nanoparticles. Ultra-broadband supercontinuum generation (SCG) from hollow-core fiber (HCF) in above-ambient pressure regime is achieved. Numerical investigations of SCG and pulse compression in HCF are carried out for providing efficient scaling laws for sub 100 fs regime2. A redefinition of the soliton order is introduced to implement a universal scaling law for the pulse compression dynamics over a range of gas pressures3. The third-order nonlinear traces and saturation limit for third-order processes is determined from the laser-induced transient grating experiments4. Experimental investigations on excitonic quasiparticle dynamics through transient absorption spectroscopy in MoS2 nanoparticles is used to determine the effect of electron-hole liquid on the band-gap renormalization of the system.


Reference:
1. Strickland D, Mourou G. Compression of amplified chirped optical pulses. Opt Commun. 1985;55(6):447-449. doi:https://doi.org/10.1016/0030-4018(85)90151-8
2. Dey P, Vijayan C, Krishnan S. Scaling of self-compression of near-IR femtosecond pulses in hollow-core fibers down to the single-cycle limit. 2022;24(4):044005. doi:10.1088/2040-8986/ac51e8
3. Dey P, Vijayan, Krishnan S. Effective soliton order and universal scaling laws for pulse self-compression over large dispersion variations. In: Peacock AC, Broderick NGR, Dudley JM, eds. Nonlinear Optics and Its Applications 2022. Vol 12143. SPIE; 2022:75. doi:10.1117/12.2632678
4. Dey P, Vijayan C, Krishnan S. Femtosecond transient grating studies in CS2. 2019 Work Recent Adv Photonics, WRAP 2019. 2019. doi:10.1109/WRAP47485.2019.9013845