高稳定度大能量三波长脉冲激光系统研究

Three wavelength pulse laser system with high stability and high energy

设计了一套高稳定度大能量输出的三波长Nd:YAG激光系统,用作激光清洗光源。该系统包括振荡级、放大级及后续波长切换系统。为解决激光棒热致双折射效应造成的输出能量下降和输出不稳定,在输出镜和激光工作物质之间插入λ_(1/4)波片,并对波片的补偿效果进行了研究。结果表明:插入波片后振荡级输出能量提高了10%,稳定度明显提高。重复频率为10 Hz时,1064 nm激光经放大后单脉冲能量可达700 mJ,其单次通过倍频晶体BBO,得到532 nm激光的单脉冲能量为325.6 mJ,四倍频后得到266 nm激光的单脉冲能量为84 mJ。1 h内测得的三波长激光输出能量不稳定度均小于0.6%。

A set of three wavelength Nd：YAG laser system with high stability and high energy output is designed, which is used as laser cleaning source. The system includes an oscillator, an amplifier and subsequent wavelength switching system. In order to solve the output energy decreasing and instability caused by thermal birefringence effect of the laser rod, a quarter wave plate is inserted between the output mirror and laser medium, and the compensation effects of the waveplate are investigated. Results show that output energy of the oscillator increases by 10% and the stability is improved obviously after inserting the waveplate. When the repetition frequency is 10 Hz, the single pulse energy of 1064 nm laser after amplificating reaches 700 mJ. It passes through the frequency doubling crystal BBO, and 325.6 mJ single pulse energy of 532 nm laser is obtained. The single pulse energy of 266 nm laser is 84 mJ after fourth harmonic generation. Three wavelength laser output energy instability is less than 0.6% in one hour.