Analysis of Parasitic Oscillation and Evaluation of Amplifier Module of Zig-Zag Slab Laser System

A high average-power solid-state laser system for attaining the current goal of 20 J output energy at 10 Hz with a pulse width of 10 ns has been designed to demonstrate scalability to 100 J output energy. We proposed ring and cascade layouts that were useful for a four-pass zig-zag slab laser amplification system with effective extraction of output energy from a laser medium of an amplifier module. The reduction of thermal effects and the suppression in thermal fracture were evaluated by the measurements of temperature distributions of the laser slab. We analyzed the parasitic oscillation of the slab laser and found the threshold values of the parasitic oscillation. We designed a dual module system in consideration of these results, and examined the extraction energy from the system that incorporated an assembly of serrated apertures to suppress the laser-induced damage of optical components and the laser slab.