532 nm激光泵浦H_(2)∶CH_(4)∶CO_(2)气体混合物的可见光宽波段拉曼激光  

Visible Broadband Raman Lasers of H_(2)∶CH_(4)∶CO_(2)Gas Mixture Pumped by 532-nm Laser

作　　者：郑天成 蔡向龙 李仲慧 沈陈诚 刘栋[1] 刘金波[1] 郭敬为[1] Zheng Tiancheng;Cai Xianglong;Li Zhonghui;Shen Chencheng;Liu Dong;Liu Jingbo;Guo Jingwei(Key Laboratory of Chemical Lasers,Dalian Institute of Chemical Physics,Chinese Academy of Sciences,Dalian,Liaoning 116023,China;School of Science,Changchun University of Science and Technology,Changchun,Jilin 130022,China;University of Chinese Academy of Sciences,Beijing 100049,China)

机构地区：[1]中国科学院大连化学物理研究所化学激光重点实验室,辽宁大连116023 [2]长春理工大学理学院,吉林长春130022 [3]中国科学院大学,北京100049

出　　处：《中国激光》2021年第21期46-54,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(22073101,21973093);中国科学院化学激光重点实验室开放课题基金(KLCL-2018-N11)。

摘　　要：532 nm激光泵浦H_(2),CH_(4)和CO_(2)三种拉曼活性气体混合物时产生的拉曼激光覆盖较宽的可见光波段,可以作为多光谱激光的照明光。分别讨论了单种气体中的受激拉曼散射和四波混频过程,比较了各阶拉曼分量随压力和泵浦能量的变化。发现在低压条件下,当高能量激光泵浦时,每种气体的各阶斯托克斯分量(尤其是一阶斯托克斯光)的转换效率基本保持稳定。在混合拉曼活性气体的实验中,通过控制不同气体之间的压力比,实现了13条光谱线的同时输出,其中574,630,683,771 nm激光在200 mJ以上的高能量区域具有非常接近的转换效率(6.5%~8%)。Objective Mixtures of H_(2),CH_(4),and CO_(2)gases pumped using a 532-nm laser were studied as visible broadband Raman lasers to illuminate multispectral lasers.To conduct mixed-gas experiments,we must understand the Raman line-widths and gain coefficients of the three gases H_(2),CH_(4),and CO_(2),which are critical for adjusting the ratio of these three gases.The optimization process for mixing H_(2),CH_(4),and CO_(2)gases depends on two parameters:the input pump energy and the partial pressures of these gases.Notably,the most important step is to fully present the pressure-and pump energy-dependence of the Raman components of each order in H_(2),CH_(4),and CO_(2)gases.We hope to achieve simultaneous outputs of some spectral lines with nearly equal conversion efficiencies by controlling the pressure ratio between the three gases during the experiment of mixing the three Raman-active gases.Methods A schematic of the experiments used to study the multiwavelength Raman lasers generation using CH_(4),CO_(2),and H_(2)gases and their mixture in a single Raman cell is shown in Fig.1.The radiation source was Nd:YAG second harmonic at 532 nm,obtained from Beamtech Optronics Co.,Ltd.,with a spot diameter of~8 mm,a divergence angle of less 1 mrad,and a pulse duration of 6 ns.All the experimental results were achieved at a fixed repetition frequency of 1 Hz.First,the pump beam was passed through a Pellin-Broca prism to avoid backwardshifted radiation.Then,it was focused using a lens L1(f=1000 mm)at the center of the 1.80-m long Raman cell.Thereafter,the pump and Stokes beams were recollimated at the exit of the cell window using the same lens L2(f=1000 mm)and dispersed via the same Pellin-Broca prism.Finally,the dichroic mirror was used to measure the backward scattering.Results and Discussions Fig.3 presents the energy conversion efficiencies of the pump energy to various Raman components against the gas pressure fixed on the pump energy of 103 mJ for the H_(2),CH_(4),and CO_(2)gases,respectively.There are clear differenc

关 键 词：激光光学 多光谱激光 受激拉曼散射 混合气体 四波混频 

分 类 号：TN249[电子电信—物理电子学]