Modular laser power scaling approach based on coherent beam coupling via stimulated Brillouin scattering

Abstract

Laser power scaling, while preserving the diffraction-limited beam quality, is one of the most challenging problems in high power laser development. Heat removal from a thermal distortion-prone active medium is a major hurdle in power scaling. This is the more so with solid-state lasers in which, unlike the gas and liquid lasers, the active medium itself cannot be recirculated to facilitate a proper no-distortion heat exchange. Another significant hurdle, if merely scaling a single power oscillator is pursued, is lateral amplified spontaneous emission (ASE), which inherently limits area scaling. Phase conjugation by stimulated Brillouin scattering (SBS) is a powerful way to achieve beam quality improvement while also providing coherent beam combination due to SBS-assisted four-wave mixing. Technical parameters of fully optimized system with nearly diffraction limited output beam are being presented.