为获得稳定输出的全固态蓝光激光器, 在考虑了准三能级Nd:YAG晶体的自吸收损耗、热致透镜效应的基础上, 设计了4镜环形谐振腔, 采用激光二极管(LD)端面抽运复合Nd:YAG激光晶体, 在腔内插入布儒斯特片作为起偏器, 由λ/2波片和TGG晶体组成单向器, 通过周期极化KTP(PPKTP)内腔倍频, 实现了连续单频运转的473 nm蓝光激光器。当激光二极管的抽运功率为20 W时, 最大连续单频473 nm蓝光输出功率为770 mW, 长期功率稳定性优于±2.2%。利用电子伺服系统将激光器的频率锁定在共焦法-珀(F-P)腔的共振透射峰上, 蓝光激光的频率稳定性优于±5 MHz/min。

Considering the reabsorption and thermal lens of Nd:YAG crystal when the laser operates on the transitions at 946 nm, a ring laser cavity formed by four mirrors was designed. Using a Brewster plate as a polarizer, a half-wave-plate and a TGG crystal as the optical diode and PPKTP as the frequency doubling crystal, a laser diode end-pumped 473 nm continuous wave single frequency Nd:YAG laser was demonstrated experimentally. The single frequency output power at 473 nm is 770 mW with pump power of 20 W. The long term power fluctuation is less than ±2.2%. After the laser was locked to the confocal Fabry-Perot cavity resonance, the measured frequency stability of blue laser is better than ±5 MHz/min.