Spectroscopic Studies of Plasmas Created by a Powerful Picosecond Krypton-Fluoride Laser.

In this thesis, the development of a picosecond KrF^* laser system for use in the excitation stage of the Two-Laser Approach to extend the wavelength of the soft X-ray laser below 100 A and its application to the study of the interaction with solid targets are presented. The picosecond KrF^* laser system has been developed over the past three and a half years. The first stage of the development has been completed and produces pulses of 20-30 mJ in 1.0-1.2 ps at 248 nm. Diagnostic techniques to characterize the basic parameters of the picosecond KrF^* laser have been developed. Spectroscopic studies of plasmas created from the interaction of the picosecond KrF^* laser with solid targets were carried out in preparation for the Two-Laser Approach. This study provides a basis for the understanding of the interaction of the picosecond KrF^* laser with matter. Spectra from highly charged ions and the effect of high density plasma on the radiation of ions are presented. The effect of prepulse, contained in the amplified spontaneous emission of the two KrF^* amplifiers, on the generation of the plasma is studied and analyzed based on the observed spectra. The study of the interaction with layered targets is carried out to closely examine the interaction of the picosecond KrF^* laser with targets. An initial test of all subsystems for the Two-Laser Approach has been performed.