Abstract

A zig-zag geometry Nd:YAG slab amplifier has been tested in a phase-conjugated master oscillator power amplifier (PC MOPA) configuration. The slab amplifier has 0.6 × 2 × 15-cm dimensions, is flashlamp pumped from both sides, and uses diffuse reflectors to provide relatively uniform gain. The amount of energy stored is typically 1.5 J/pulse, and the repetition rate can be as high as 40 Hz (power supply limited). Figure 1 shows the schematic layout of the PC MOPA. A commercial, injection-seeded Quantel laser is used as the master oscillator. The master oscillator pulse is spatially filtered, expanded, beam shaped, and injected into the amplifier. The amplified beam is phase conjugated in a high purity N₂ cell, which operates at approximately 1000 psi. The phase-conjugated beam propagates through the amplifier where most of the aberrations are corrected and is extracted by polarization-rotating techniques. Diagnostics include stimulated Brillouin scattering (SBS) reflectivity and fidelity and extracted energy and beam quality.

© 1991 Optical Society of America