Abstract

Optical phase conjugation using stimulated Brilluoin scattering (SBS) is widely used in high average power solid state lasers and multipass amplifiers for correction of problems brought on by thermally induced birefringence and depolarization and for pulse compression.¹ Multi-kilowatt average power with diffraction-limited beams are now routinely obtained in Nd:YAG laser systems where a SBS mirror is an integral part of the system. The pump lasers used in these systems all have narrow bandwidths, typically <1 GHz. The reason for this is well-known^2,3: the SBS threshold for a noisy (multi-frequency) pump is higher than that for a single-longitudinal-mode pump or one with just a few modes. So, in order to obtain high reflectivity for the SBS mirror using minimal power, narrow-bandwidth lasers are used. We have taken note of this property of SBS and explored its utility to solve another important problem in laser amplifiers: the suppression of amplified spontaneous emission.

© 1996 Optical Society of America