100 W class average power coherent 2-beam combination laser system at 1 kHz repetition rate operation using self-phase-controlled stimulated Brillouin scattering phase conjugate mirrors with pre-pulse

Abstract

Coherent beam combining is one of the most promising technique to develop a high power laser with high repetition rate and high energy. To combine beams coherently, the wavefronts of the beams should be same and the relative phase difference should be 0. A stimulated Brillouin scattering phase conjugate mirror (SBS-PCM) is proper to the coherent beam combining, because the double pass amplified beam can be same with the input beam by its phase conjugation property. Also, by self-phase-control method, the inherent initial phase can be fixed and is easy to control the relative phase difference by piezoelectric transducer. In this research, the SBS reflection properties are investigated for the main amplifier of the kHz class LD-pumped laser system, the Kumgang laser system. As a result, a steep edge at the pulse temporal waveform of the SBS reflected pulse is observed. To prevent damages in the optical components and the gain media during double pass amplification, the pre-pulse technique is applied and the double pass amplified beam properties are investigated. With these results, the coherent 2-beam combination of the Kumgang laser double pass amplified beam is performed.