914 nm LD泵浦RTP电光调Q的高效率Nd:YVO4激光器

报道了一种激光二极管（LD）端面连续抽运的高重频、高光光效率电光调Q Nd:YVO4激光器。采用RbTiOPO4（RTP）晶体对作为调Q元件，通过减小热效应和模式匹配技术，实现了高效率的高重频窄脉宽1 064 nm脉冲激光输出。一方面采用低吸收系数的914 nm波长抽运Nd:YVO4晶体，使晶体内热分布均匀，从而获得高量子效率的同时减小了热效应影响。另一方面通过优化泵浦光斑半径，实现泵浦光和振荡光好的模式匹配。在重频200 kHz时，获得了最高输出功率16 W，脉宽9 ns，单脉冲能量80 J，光束质量M21.2的稳定脉冲激光，泵浦吸收功率31 W，对应的光光转化效率为51.6%。据笔者所知，这是RTP电光调Q实现的最高效率的脉冲激光器。

Highly efficient RTP electro-optic Q-switched Nd: YVO4 laser by end-pumping at 914 nm

An electro-optic (EO) Q-switched Nd:YVO4 laser with high repetition rate, end-pumped by continuous-wave (CW) laser diode (LD) was reported. Using RbTiOPO4 (RTP) single crystal as an EO Q-switch, by matching mode of oscillation light and pump light, 1 064 nm laser output with high efficiency, high repetition and short pulse width was realized. On the one hand, low absorption coefficient of 914 nm wavelength was adopted to pump Nd:YVO4 crystal, so that the heat distribution inside the crystal was uniform, thereby achieving high quantum efficiency while reducing the thermal effect. On the other hand, the pump light spot radius was optimized to match mode of pump light and oscillation light. At the repetition rate of 200 kHz, the maximum average output power of 16 W, full width at half maximum of pulses of 9 ns, single pulse energy of 80 J and beam quality M21.2 are achieved at an absorption pump power of 31 W, corresponding to an optical conversion efficiency of 51.6%. To the best of our knowledge, this is the highest efficiency reported on the EO Q-switched laser by using RTP crystals.