Characterization of preformed plasmas from Si and Al targets using the Nomarski interferometry

Abstract

Plasma formation plays an important role in laser-matter interactions such as the laser-driven proton acceleration, X-ray lasers, high energy density physics, etc. The scope of this research covers space-time-resolved plasma diagnostics using the pump-probe technique. The main goal of the work is to study the interaction of intense laser pulses with solid targets, such as an aluminum foil and a silicon wafer, using the Nomarski interferometry. Solid targets are shot with the 219 ps Ti:sapphire laser pulse with an intensity in the range of 10^(11-12) W/cm^2. The compressed 35 fs probe pulse is directed perpendicular to the pump beam line through the preformed plasma and further to the Nomarski interferometer. The obtained interferograms are analyzed by the Fast Fourier Transform and Abel inversion algorithms to extract phase shift information and electron density distribution. In this thesis, an analytical approach and one-dimensional collisional plasma concept are used to compare with the experimental results.