啁啾周期极化铌酸锂晶体在1064 nm倍频实验中的效率与温度鲁棒性  

Efficiency and Temperature Robustness of Chirped Periodically Polarized Lithium Niobate Crystals in 1064 nm Frequency Doubling Experiment

作　　者：苏伟伦 刘峻铭 邹娱 刘励强 洪丽红 李志远 Su Weilun;Liu Junming;Zou Yu;Liu Liqiang;Hong Lihong;Li Zhiyuan(School of Physics and Optoelectronics,South China University of Technology,Guangzhou 510641,Guangdong,China;Guangdong Jingchuang Optical Machinery Co.,Ltd.,Guangzhou 510510,Guangdong,China;State Key Laboratory of High Field Laser Physics,Shanghai Institute of Optics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]华南理工大学物理与光电学院,广东广州510641 [2]广东晶创光学机械有限公司,广东广州510510 [3]中国科学院上海光学精密机械研究所强场激光物理国家重点实验室,上海201800

出　　处：《光学学报》2024年第11期187-195,共9页Acta Optica Sinica

摘　　要：为了提升532 nm激光的产生效率和功率稳定性,以基于倒格矢实现准相位匹配的手段为基础,设计了合适的啁啾周期极化铌酸锂(CPPLN)晶体的结构并进行仿真,采用自制的1064 nm激光器对该结构的晶体进行腔外倍频实验。在输入的1064 nm连续光功率为22.53 W的条件下可以获得功率为148 mW、波长为532 nm的光,光光转换效率约为0.66%,是三硼酸锂(LBO)的15.58倍。进一步验证了CPPLN晶体的温度鲁棒性,532 nm倍频光的功率关于温度的半峰全宽为8.40℃,且在该范围内功率呈现振荡的趋势,其原因是加工精度的限制导致倒格矢分布不连续。所得到的输出倍频光的光斑为标准的高斯光斑,其并不受温度的影响。结果表明,该设计结构的CPPLN晶体相对于传统LBO晶体具有更高的倍频效率与温度鲁棒性。Objective The 532 nm solid-state laser is one of the most widely used lasers in current industry and scientific research.The most common route to build a 532 nm solid-state laser system is to generate a 1064 nm laser by pumping Nd∶YVO4 or Nd∶YAG crystal with 808 nm/880 nm laser diode,and then generating continuous or pulsed 532 nm lasers by secondharmonic generation(SHG)through frequency doubling crystal.At present,the most common frequency doubling crystal is lithium borate(LBO),which is superior in low cost,high damage threshold,and wide transmittance bands.However,due to the low nonlinear coefficient of LBO and the temperature phase matching scheme,the SHG efficiency is low and highly sensitive to temperature.In this study,we design and simulate a suitable structure of chirped periodically poled lithium niobate(CPPLN)that exhibits certain quasi-phase matching bandwidth and large effective nonlinear coefficient,and a CPPLN crystal with designed structures is applied for extra-cavity SHG experiment with a home-made 1064 nm laser.The result shows that the CPPLN with a designed structure has better SHG efficiency and temperature robustness compared with the traditional LBO crystal.The findings are expected to be helpful to the design of the 532 nm laser as well as to the power and temperature robustness improvement at other wavelengths.Methods We first analyze the coupling equation of the SHG,which shows that a larger gain bandwidth of the CPPLN crystal leads to better temperature robustness but lower SHG efficiency.According to the analysis,we design the structure of the CPPLN crystal after measuring the bandwidth of the input light.To visualize the effect of the designed CPPLN crystal,the Fourier transform of the effective Fourier coefficients of the crystal is taken to get their distribution in the reciprocal lattice vector domain.The above measures have led to the design of a CPPLN crystal structure that combines good temperature robustness with a high frequency doubling efficiency.To verify the actual res

关 键 词：非线性光学 啁啾周期极化铌酸锂晶体 温度鲁棒性 腔外倍频 

分 类 号：O437.1[机械工程—光学工程]