掺铥光纤激光放大器在宽波段吸收光谱技术中的应用  

Tm-Doped Fiber Laser Amplifier Applied to Hyperspectral Absorption Spectroscopy

作　　者：王亚民 吴昊龙 陶蒙蒙 刘洋阳 李国华 王晟 叶景峰 WANG Yamin;WU Haolong;TAO Mengmeng;LIU Yangyang;LI Guohua;WANG Sheng;YE Jingfeng(State Key Laboratory of Laser Interaction with Matter,Xi’an 710024,China;Wang Zhijiang Laser Innovation Center,Shanghai Institute ofOptics and Fine Mechanics,Chinese Academy of Sciences,Shanghai 201800,China)

机构地区：[1]激光与物质相互作用国家重点实验室,西安710024 [2]中国科学院,上海光学与精密机械研究所,王之江激光创新中心,上海201800

出　　处：《现代应用物理》2024年第2期87-93,共7页Modern Applied Physics

基　　金：国家自然科学基金资助项目(62105268,52106222,91841303);激光与物质相互作用国家重点实验室基金资助项目(SKLLIM2009,SKLLIM2110)。

摘　　要：利用掺铥光纤在2μm波段的宽带发射特性和光纤可饱和吸收体的线宽压缩特性,研制了宽带调谐窄线宽掺铥光纤激光放大器,该激光放大器可将窄线宽、宽带可调谐种子光源的功率放大至290 mW,放大后的光源连续运行30 min,均方根稳定性优于1%。利用激光放大器输出的32路激光中的任意一路测试了水分子在2μm波段的宽吸收光谱,并利用测试结果反演得到了该光源在动态扫描过程中的线宽约为0.06 nm。利用该激光放大器分别测试了空气和酒精火焰中温度和水分子摩尔分数。结果表明:常温下,空气和酒精火焰中温度的平均值分别为301.2,1263.3 K,相对偏差分别为1.28%,3.08%,水分子的摩尔分数平均值分别为2.11%,5.58%。利用该光源可有效获取水分子在2μm波段的宽波段激光吸收光谱,利用这些吸收光谱数据能够较为精确的反演出环境温度、水分子摩尔分数等信息,结果验证了该激光光源在燃烧流场2维层析诊断测量应用中的可行性。A broadband tunable narrow line width thulium doped fiber laser amplifier is developed by using the broadband emission characteristics and the line width compression characteristics of fiber saturable absorbers of Tm-doped fibers in the 2μm band.The laser amplifier can amplify the power of the narrow line width and broadband tunable seed light source to 290 mW with a root mean square(RMS)stability less than 1%,and the amplified light source can run continuously for 30 minutes.The amplifier output is splitted into 32 beams,and a hyperspectral absorption spectroscopy test of water molecules in the 2μm wavelength band is conducted using any of these beams.The line width of the light source during dynamic scanning process is about 0.06 nm through inversion.The temperature and water molecular fraction in air and alcohol flames are measured using this laser amplifier.The test results show that at room temperature,the average temperature in air and alcohol flames are 301.2 and 1263.3 K,with relative deviations of 1.28%and 3.08%,respectively.The average molar fractions of water molecules are 2.11%and 5.58%,respectively.The hyperspectral absorption spectroscopy of water molecules in the 2μm band can be effectively obtained by using this light source.By using these absorption spectroscopy data,it is possible to accurately deduce information such as ambient temperature and water molecular mole fraction.The results verify the feasibility of the light source in two-dimensional tomography applications in combustion flow fields.

关 键 词：吸收光谱 可调谐二极管激光吸收光谱技术 宽波段吸收光谱技术 燃烧流场 掺铥光纤激光放大器 

分 类 号：O43[机械工程—光学工程] TN25[理学—光学]