激光差频技术实现高平均功率3.8μm纳秒中波红外激光输出实验研究  

Experimental Investigation on the High Average Power ns Mid-Infrared Laser Output at 3.8 μm Through Difference Frequency Generation

作　　者：沈永行[1] 吴波[1] 胡澄之 乐文杰 江以逻 Shen Yonghang;Wu Bo;Hu Chengzhi;Yue Wenjie;Jiang Yiluo(State Key Laboratory of Modern Optical Instrumentation,College of Optical Science and Engineering,Zhejiang University,Hangzhou,Zhejiang 310027,China)

机构地区：[1]浙江大学光电科学与工程学院现代光学仪器国家重点实验室,浙江杭州310027

出　　处：《中国激光》2022年第1期186-193,共8页Chinese Journal of Lasers

基　　金：国家自然科学基金(62075190);国家重大研究计划(2018YFC1004800)。

摘　　要：报道了利用脉冲激光差频技术获得波段在3.8μm纳秒中波红外激光输出的实验研究。分别研制了基于增益调制半导体激光器和“8字腔”锁模掺Yb光纤激光器的1094 nm纳秒脉冲激光种子,经光纤激光放大后获得平均功率为40 W的高光束质量线偏振泵浦光。研制了脉冲同步的1535 nm的信号光种子及输出平均功率为3 W的掺Er光纤激光放大器。将放大后的1535 nm线偏振信号光与1094 nm泵浦光共线入射到作为非线性晶体的周期性畴极化反转掺镁铌酸锂(PPMgLN)晶体中,利用激光差频技术实现了平均功率为5 W的3.8μm纳秒脉冲激光输出。Objective Because there exist many strong narrow intrinsic adsorption lines of gases,vapors,organic pollutants,poison chemicals,and biological virus molecules,mid-infrared band has long been called the“finger-print”zone in spectroscopy,which can be used to detect these substances with an extremely high sensitivity.The lasers situated around 3μm are also applied for specific local zone therapy.The laser will be completely absorbed within a thin layer of several microns thickness in biological tissues because they have very strong adsorption to photons at this wavelength.The lasers at 3.6μm and 3.8μm are also excellent light sources for laser remote detection and freespace communication due to the superior atmospheric windows at these wavelengths.Difference Frequency Generation(DFG)is one kind of nonlinear optical parametric technique,which can be applied for efficient laser frequency conversion,especially from near-infrared to mid-infrared.It can overcome the long term stability problem associated with the optical cavity misalignment in optical parametric oscillator(OPO)but still keep high parametric conversion efficiency from near-infrared pump to mid-infrared idler with the help of strong signal light.Many works have been reported on DFG between Yb-doped fiber lasers and Er-doped fiber lasers for high average mid-infrared laser output but the wavelengths are mainly limited to 3.3μm or shorter.For longer idler wavelength such as3.8μm,Yb-doped fiber laser has to be worked at long spectral gain edge around 1090 nm while the Er-doped fiber laser needs to work around 1530 nm in the short gain edge,which results in excess difficulties in realizing high average power fiber lasers as the pump and the signal.The objective of this work is to demonstrate the feasibility of efficient ns DFG at 3.8μm.Methods Efficient DFG for 3.8μm laser output was realized in a periodically poled magnesium oxide doped lithium niobate(PPMgLN)by applying Yb-doped fiber laser at 1094 nm as the pump and Er-doped fiber laser at 1535 n

关 键 词：激光光学 中波红外激光器 光纤激光器 激光差频 

分 类 号：TN248[电子电信—物理电子学]