High peak power diode-pumped Nd:YAG laser with Brillouin phase conjugation/pulse compression mirror

Abstract

Summary form only given. We studied a Nd:YAG laser experimental setup with phase conjugation/pulse compression SBS mirror presented. The pulses of a master oscillator (MO) with duration of 3.2 ns were directed to the first amplifier and further to the SBS cell consisting of stainless steel or glass casings filled with highly purified liquid tetrachlorides such as SiCl/sub 4/, SnCl/sub 4/, and GeCl/sub 4/. In order to optimize the SBS geometry we took into account the necessity of suppressing forward and backward SRS, self-focusing, optical breakdowns. We have observed that frequency of laser optical breakdowns on microparticles grows nonlinearly with increase of pulse repetition rate above a certain level depending on the polishing quality of the internal surface of SBS casing. Such negative effects became important due to the relative low polishing quality above. By replacing stainless steel with a glass casing with better polishing but filled with the same liquid, we could reach stable SBS with repetition rate up to I kHz while the convection flow was relatively low. For a stainless steel SBS casing filled with SiCl/sub 4/ at 100 Hz we were able to achieve 30% reflectivity. for 4-fold exceeding the SBS threshold; the reflected pulse duration was 350 ps, and the pulse-to-pulse duration stability was 20%. Further, the pulse was amplified in a double-pass amplifier up to 5 mJ and directed to a power amplifier (PA), consisting of a 7 mm /spl times/ 12 mm Nd:YAG rod.