Femtosecond pulse propagation in air towards filamentation nonlinear optics

Abstract

Intense Femtosecond pulse propagation in air leads to a highly dynamic newlinephenomenon called filamentation. The thesis discusses filamentation in air and the newlinevarious aspects of filamentation which arise from the long range highly intense newlinepropagation of femtosecond pulses. This chapter briefly discusses generation of newlineintense femtosecond pulses and the nonlinear phenomenon that arise during the fs newlinepulse propagation in a medium leading to the formation of filaments. The prolonged newlinepropagation arising due to the dynamic interplay between the third order material newlineresponse to the electric field and the plasma build up is a home for many non-linear newlineprocesses. The electromagnetic propagation equation was used to account for the newlinemultiple processes that arise during filament propagation such as multiphoton newlineionization, Kerr self-focusing, self-phase modulation, higher harmonic generation and newlineabsorption. Filamentation is a highly dynamic regime because of which simulation newlinealone cannot help understand the processes in filamentation which can be modulated newlineor enhanced. We have therefore attempted to empirically characterize filaments newlinegenerated under different input laser properties and correlate them to the newlinecorresponding emissions from filaments. This chapter establishes the basis and newlinemotivation for the thesis which is to holistically characterize filamentation with a goal newlinetowards important applications such as remote sensing. newline