热近非稳腔高重频双波长复合输出激光器研究

Research of high-repetitive frequency dual-wavelength composite output laser with near thermal unstable resonator

1064 nm/532 nm双波长固态激光器在多个领域应用广泛。针对目前该类激光器分光路可切换输出研究较多,而复合输出研究缺乏的现状,通过建立含热透镜的等价谐振腔模型,结合谐振腔稳定性和"热近非稳谐振腔"理论确定了最佳腔长,利用软件仿真分析了倍频晶体的长度、输出镜基频透过率、调Q频率的大小对复合输出的影响,根据双路激光干扰的实际需求,确定了最佳复合输出参数,从而完成了一台1064 nm/532 nm高重频双波长复合输出激光器的设计。实验表明,KTP晶体长度选为12 mm,输出镜基频透过率选为15%,调Q频率选为50 k Hz时,在最大泵浦功率下,基频光输出的平均功率为28.82 W,倍频光的输出的平均功率为2.23 W。测量得到的激光近场发散角与光斑半径的乘积近似等于同样位置处基模高斯光束发散角与光斑半径的乘积,这说明所设计的激光器在最大泵浦功率条件下是以近似基模的方式运转,具有较好的光束质量。

With its wide-spread application in various fields,1064 nm/ 532 nm dualgiven rise to a bunch of studies upon its optical path switching output. In contrast, there is still a lack of study of com-posite output. A new dual-wavelength composite output laser with high-repetitive frequency was designed. Firstly,an equivalent resonator model with thermal lens was established, and then the optimum cavity length was determined bycombining the stability of resonator and the theory of anear thermal unstable resonator” ,then the influence of the fre-quency doubling crystal length,the fundamental wave（FW） transmissivity of the output mirror,and quency on the composite output was analyzed by means of software simulation, finally, the optimparameters ware determined according to the actual requirements of the double channel laser jammmental results show that when the length of KTP crystal is chosen as 12 mm, the FW transmissivity of the output mirror is fixed to 1.5%, and the Q frequency is selected as 50 kHz,the average output power of the FW is 28. 82 W, and the average power of the output of second-harmonic wave（SHW） is 2. 23 W under maimum pumping power. The product of the laser near field divergence angle and the laser spot radius is close to the product of the divergence angle of the fundamental model Gauss beam and the radius of the spot in the same position. The results show that the dsigned laser works in approximate fundamental mode under the maimum pumping power,and it has better beam quality