为了降低高重复频率脉冲固体激光器中热致光束畸变对光束质量的影响,在激光二极管抽运、电光调Q的Nd∶YAG激光双通放大系统中对多模石英光纤相位共轭镜进行了实验研究。激光重复频率100 Hz、脉宽20 ns。实验结果表明

To reduce the thermal effect to beam quality in solid-state laser with high repetition rate, multimode optical fiber as phase conjugator has been experimentally investigated in an laser diode-pumped, electrooptical Q-switched Nd∶YAG laser with double-pass amplifier. The laser was operated on 100 Hz repetition rate and 20 ns pulse width. Perfect correction of laser profile distortion in amplifier and beam quality close to diffraction limit has been achieved. Pulse width of phase-conjugated laser was compressed to 7 ns while compression ratio reached 3∶1. Beam glitter has also been observed in lower pumping energy close to stimulated Brillouin scattering (SBS) threshold. With increase of energy coupled into fiber, that phenomenon was weakened, and higher stability was achieved. In the case of 5.3 mJ input energy, instability less than 14% is obtained, while SBS reflectivity and depolarization ratio were 32.6% and 7% respectively.