LONG-PULSE-WIDTH NARROW-BANDWIDTH LASER

摘要

A long pulse laser system emits 500-1000ns quasi-rectangular pulses at 527nm with near diffraction-limited divergence and near transform-limited bandwidth. The system consists of one or more flashlamp-pumped Nd:glass zig-zag amplifiers (42), a very low threshold simulated-Brillouin-scattering (SBS) phase conjugator system (66), and a free-running single frequency Nd:YLF master oscillator (10). Completely passive polarization switching provides eight amplifier gain passes. Multiple frequency output can be generated by using SBS cells having different pressures of a gaseous SBS medium or different SBS materials. This long pulse, low divergence, narrow-bandwidth, multi-frequency output laser system is ideally suited for use as an illuminator for long range speckle imaging applications. Because of its high average power and high beam quality, this system has application in any process which would benefit from a long pulse format, including material processing and medical applications.