闲频光单谐振KTiOAsO_(4)涡旋光参量振荡器的研究  

Idler-Resonant Optical Vortex Parametric Oscillator Based on KTiOAsO_(4)

作　　者：苏比努尔·牙库甫 周玉霞 宣闯 冶建强 买里克古丽·艾合买提 焦夏卓 塔西买提·玉苏甫[1] Subinuer Yakufu;Zhou Yuxia;Xuan Chuang;Ye Jianqiang;Mailikeguli Aihemaiti;Jiao Xiazhuo;Taximaiti Yusufu(Xinjiang Key Laboratory for Luminescence Minerals and Optical Functional Materials,School of Physics and Electrical Engineering,Xinjiang Normal Unibersity,Urumqi 830054,Xinjiang,China)

机构地区：[1]新疆师范大学物理与电子工程学院,新疆发光矿物与光功能材料研究重点实验室,新疆乌鲁木齐830054

出　　处：《中国激光》2024年第5期24-29,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(12264049,11664041)。

摘　　要：设计了一种由1μm涡旋光泵浦的闲频光单谐振KTiOAsO_(4)涡旋光参量振荡器,并基于该光参量振荡器在近/中红外波段实现了高光束质量、高能量、窄光谱带宽的涡旋光输出。选取不同曲率半径的输入镜和平面输出镜分别建立平平腔和平凹腔两种腔结构,基于所建结构可以控制泵浦光的轨道角动量(OAM)选择性地传递给输出的信号光或闲频光。当泵浦光最大能量为20.6 m J时,在近红外波段产生了3.04 m J的信号涡旋光(1.535μm),同时在中红外波段产生了0.82 m J的闲频涡旋光(3.468μm),它们对应的转换效率分别为28.21%和7.62%。基于泵浦光与谐振闲频光在两种腔型中的空间重叠效率,从理论上解释了泵浦光OAM的传递原理。测量得到输出信号光和闲频光的光谱带宽(半峰全宽)分别为λs=0.85 nm和λi=1.08 nm,其中闲频光在两个正交方向上的光束质量因子分别为Mx2≈2.1和My2≈2.2。Objective Optical vortex lasers,with good beam quality in the mid-infrared spectral region,has many interesting applications such as super-resolution molecular absorption microscopy and molecular spectroscopy.The optical parametric oscillator(OPO)has been established as the most direct method to change the wavelength and transition the orbital angular momentum(OAM)of an optical vortex pump beam.A single-idler resonant cavity can produce a high-quality mid-infrared vortex output.However,one of the main challenges has been to manage the transfer of OAM from the pump beam to the mid-infrared idler output,especially given the significant wavelength difference—over three times—between the 1μm pump and 3.5μm idler beam.This discrepancy complicates achieving high spatial overlap efficiency between the pump and idler vortex modes in the optical vortex pumped idler-resonant parametric oscillator.By choosing cavity mirrors with the correct radius of curvature,a half-symmetric OPO system can facilitate the transfer of the pump beam s OAM to the idler output,ultimately producing a high-quality mid-infrared vortex beam.Methods In the paper,the idler single resonant optical vortex parametric oscillator based on KTA was examined.A conventional flash-lamped Q-switched Nd∶YAG laser(with a Gaussian spatial form,pulse duration of 25 ns,wavelength of 1.064μm,and pulse repetition frequency of 50 Hz)was employed as the pump source.The laser output was converted into a first-order optical vortex beam using a spiral phase plate.This beam was then focused into a non-critically phase-matched KTA crystal with dimension of 5 mm×5 mm×30 mm.A plane-parallel cavity was formed using M1,which had high transmission for the pump and high reflection for the idler output beam,and an OC that had high transmission for the pump and signal beams,and a partial reflectivity(80%)for the 3.5μm(idler)beam.A plane-concave cavity was created using a plane-concave M2(with a curvature radius of 500 mm)that was antireflection coated for the pump field

关 键 词：光学器件 涡旋光 闲频光谐振 光参量振荡器 KTiOAsO_(4) 

分 类 号：O437[机械工程—光学工程]