MgO:PPLN中红外光参量振荡器的闲频光纵模特性研究  

Study on the longitudinal mode characteristic of idler wave in MgO:PPLN infrared optical parametric oscillator

作　　者：郑浩 赵臣 张飞[1,2] 李鹏飞 颜秉政[1,2] 王雨雷 白振旭 吕志伟 Zheng Hao;Zhao Chen;Zhang Fei;Li Pengfei;Yan Bingzheng;Wang Yulei;Bai Zhenxu;Lv Zhiwei(Center for Advanced Laser Technology,Hebei University of Technology,Tianjin 300401,China;Hebei Key Laboratory of Advanced Laser Technology and Equipment,Tianjin 300401,China;National Key Laboratory of Electromagnetic Space Security,Tianjin 300308,China)

机构地区：[1]河北工业大学先进激光技术研究中心,天津300401 [2]河北省先进激光技术与装备重点实验室,天津300401 [3]电磁空间安全全国重点实验室,天津300308

出　　处：《红外与激光工程》2023年第12期32-37,共6页Infrared and Laser Engineering

基　　金：国家自然科学基金项目(61927815,62075056);天津市自然科学基金项目(22JCYBJC01100)。

摘　　要：文中介绍了一种纳秒脉冲端面泵浦MgO:PPLN外腔光参量振荡器。基频光采用激光二极管泵浦的声光调Q Nd:YVO_(4)纳秒激光器,在声光Q开关的工作重复频率为120 kHz时,实现脉宽8.1 ns、最高输出功率7.03 W的1.064μm激光输出。通过将基频光聚焦至MgO:PPLN晶体内,外腔泵浦得到了脉冲宽度为4.7 ns,输出功率0.7 W的3μm闲频光。基频光-闲频光转换效率为9.95%,将基频光与闲频光的时域波形图傅里叶变换后对比,观察到光参量振荡过程对闲频光高阶纵模的抑制现象。该研究对实现窄线宽低噪声的中红外激光具有一定的参考价值。Objective Narrow linewidth solid-state lasers are characterized by their excellent coherence and beam quality.Narrow linewidth lasers of certain wavelengths are necessary to meet the absorption or transmission requirements of specific ions,molecules,and materials.Therefore,it is of great significant to investigate the longitudinal mode characteristics of lasers at different wavelengths and operating modes.The 3-5μm spectral range falls within the atmospheric window.Mid-infrared lasers in this band have been widely used for environmental gas monitoring,spectral analysis and optoelectronic countermeasures.Currently,MgO:PPLN crystals are typically employed in optical parametric oscillators(OPOs)to generate mid-infrared lasers within the 3-5μm spectrum.This is attributed to their high second-order nonlinearity coefficient,large damage threshold,and widely tunable wavelength range.In addition to the tunability of the output wavelength,the optical parametric oscillation process also possesses the ability to suppress multi-longitudinal-mode operation within the cavity.While previous experiments have demonstrated that multi-longitudinal-mode operation can be suppressed by placing optical parametric crystals inside the cavity,However,more specific studies are limited.In this study,a comparative analysis of the variation of longitudinal mode properties at fundamental and idler frequencies was performed using MgO:PPLN crystals.Methods The output wavelength at different temperatures is simulated based on the phase matching equation and the dispersion equation,as depicted in Fig.1.The experimental setup is illustrated in Fig.2.An fiber coupled 808 nm laser diode continuous-wave laser was used as the pump source,with a core diameter of 200μm and numerical aperture of 0.22.A 1:2 focusing lens result in a spot radius of 400μm at the Nd:YVO_(4)crystal.The crystal has a dimension of 3 mm×3 mm×18 mm and a doping concentration of 0.3%.Plane mirrors M1 and M2 form a 1064 nm fundamental frequency optical resonator with a cavity

关 键 词：光参量振荡器 MgO:PPLN 纵模 中红外 闲频光 

分 类 号：TN248[电子电信—物理电子学]