实验研制了端抽运Nd∶YVO4放大器和侧抽运Nd∶YAG放大器相结合的高功率高光束质量皮秒激光器。这一系统充分利用了Nd∶YVO4 晶体受激发射截面大和Nd∶YAG晶体热导率大的优点。端面抽运Nd∶YVO4放大器使振荡器输出的激光获得高增益而迅速放大, 随后的侧面抽运的Nd∶YAG激光模块放大器有利于大功率抽运从而得到高功率激光输出。侧抽运Nd∶YAG放大器采用了双程放大的方式设计, 利于提高放大器的效率。为保证光束质量和光束模式匹配, 在放大器之间设计了合适的空间滤波器。激光器输出平均功率43.4 W, 光束质量因子M2<1.7的皮秒激光。

A high average power and high beam quality picosecond laser system combined with diode-end-pumped Nd∶YVO4 and laser diode-side-pumped Nd∶YAG amplifier is described. The system combines the advantages of Nd∶YVO4 crystal having large stimulated-emission cross section and Nd∶YAG crystal having good thermal conductivity. The diode-end-pumped Nd∶YVO4 amplifier allows the laser from the oscillator to obtain high gain so that the laser can amplify rapidly and the diode-side-pumped Nd∶YAG amplifier benefits to obtain high output power. The Nd∶YAG amplifier is designed as double-pass form to increase the efficiency of the amplifier. Spatial filters are adopted between amplifiers to ensure good beam quality and mode matching. Picosecond laser with average power of 43.4 W and good beam quality factor M2<1.7 is generated from this laser system.