Exploring the Interaction of Light and Matter on an Ultrafast Timescale Using Plasma Spectroscopy

The development of intense, sub-picosecond lasers has created a new realm of study concerning the interaction of light and matter. The basic characteristics of this interaction include the rapid ionization of matter, resulting in plasma formation, and the deposition of energy into a material on a timescale shorter than the thermal relaxation of the system. In this thesis, a collection of experimental studies attempt to explain some of the complex phenomena that occur during this interaction under the extreme conditions of a ~50 fs laser pulse, with an intensity ranging from 1014-1016 W/cm2, by spectroscopically analyzing the light given off by the plasma. Further attention is given to the interaction of the light with the laser-generated plasma itself, which dictates the development of many of the different processes. Some of the key aspects investigated are the spectral and polarization characteristics of the plasma light emission, second harmonic generation in plasmas, and the effect of plasma creation on dual-pulse laser ablation.