小型化宽调谐MgO:PPLN中红外纳秒光参量振荡器  

Miniaturized Widely Tunable MgO∶PPLN Nanosecond Optical Parametric Oscillator

作　　者：王菲菲 聂鸿坤 刘俊亭 杨克建 张百涛[1,2] 何京良 Wang Feifei;Nie Hongkun;Liu Junting;Yang Kejian;Zhang Baitao;He Jingliang(State Key Laboratory of Crystal Materials,Institute of Novel Semiconductors,Shandong University,Jinan,Shandong 250100,China;Key Laboratory of Laser&Infrared System,Ministry of Education,Shandong University,Qingdao,Shandong 266237,China)

机构地区：[1]山东大学晶体材料国家重点实验室,新一代半导体材料研究院,山东济南250100 [2]山东大学激光与红外系统集成技术教育部重点实验室,山东青岛266237

出　　处：《中国激光》2021年第5期201-209,共9页Chinese Journal of Lasers

基　　金：国家重点研发计划(2017YFB0405204)。

摘　　要：基于光学超晶格的光参量振荡技术是产生2~5μm中红外光源的有效途径,在大气环境监测、医疗诊断、精密光谱分析、光电对抗等领域具有重要的应用价值。针对小型化中红外激光器应用需求,开展了结构紧凑、高效率、宽调谐的纳秒光纤激光泵浦的周期极化掺镁铌酸锂光学超晶格(MgO∶PPLN)光参量振荡器(OPO)的研究。采用1.06μm纳秒光纤激光泵浦多周期(29~31.6μm)MgO∶PPLN晶体,结合周期和温度调谐,实现了闲频光2.37~4.01μm连续调谐中红外激光输出。当泵浦功率为9.95 W时,2.37~3.75μm平均输出功率均大于1.7 W,其中3.4μm平均输出功率最大,相应的功率和光光转化效率分别为3.68 W和37%。重点讨论了在2.4、2.7、3.8和4.0μm处的中红外激光输出特性,最大平均输出功率可分别达到2.87、2.45、1.87和1.22 W,相应的光光转化效率分别为17.2%、19.8%、11.2%和8.6%。本文的研究结果为小型化宽调谐中红外激光器的研发提供了重要的实验依据。Objective Mid-infrared(MIR)lasers play a role in several applications,including environmental atmosphere monitoring,medical diagnosis,spectral analysis,optoelectronic countermeasures,etc.The MIR band of wavelengths spanning 2--5μm is called the atmospheric window area,which is the transmission window with the highest atmospheric transmittance.This band can penetrate fog and smoke and is widely used in the field of free space optical communication.A MIR laser with a wavelength near 3μm is located in the most absorptive zone of water molecules.This laser has a shallow penetration depth in human tissues,leading to little thermal damage to surrounding tissues.This greatly improves the ability of the laser to melt,excise,and vaporize tissues;therefore,it is widely used in biomedical fields.The spectral response range of a military infrared guided missile detector is 3--5μm.With the yearly increase of infrared detector usage,corresponding jamming technology development is also accelerating and a laser light source of this band is urgently needed for a photoelectric countermeasure of an infrared seeker.Motivated by the demand of miniaturized MIR laser sources,a compact,high-efficiency,and widely tunable magnesium-doped periodically poled lithium niobate(MgO∶PPLN)optical parametric oscillator(OPO)pumped by a nanosecond fiber laser was studied.Methods Optical parametric oscillation with a superlattice is the most effective method for 2--5μm MIR laser generation.The pump source in this study was a linearly polarized nanosecond fiber laser with a central wavelength of 1064.2 nm.The maximum output power of the pump was 20 W,the pulse width was 200 ns,the repetition frequency was 50 kHz,and the beam quality factor,M^(2),was less than 1.1.A 1-mm-thick and 50-mm long MgO∶PPLN nonlinear crystal,with polarization periods of 29--31.6μm,was used.We chose a double-pass single-resonance flatflat cavity OPO and used the quasi-phase matching method to tune the wavelength by periodic and temperature modulation of the PPLN cryst

关 键 词：激光器 中红外激光 光参量振荡器 MgO∶PPLN晶体 宽调谐 

分 类 号：O437.7[机械工程—光学工程]