High beam quality by SBS phase conjugation of a single rod Nd-amplifier up to 140W average output power

For pumping XUV plasma light sources with solid-state lasers and also for micro-material processing, high beam quality and output power as well as simplicity of the pump lasers are crucial. The beam quality of high-power solid-state lasers can be significantly improved using phase-conjugating mirrors based on stimulated Brillouin scattering (SBS). Hence, SBS phase conjugation may prove one of the key technologies in this field. We describe a single-rod neodymium amplifier with 140 W average output power and nearly diffraction-limited beam. Because of automatic compensation of the thermal tensing by SBS phase conjugation, the output power can be tuned without changing the beam profile.