高精细度光学反馈腔衰荡光谱技术  

High finesse optical feedback cavity ringdown spectroscopy

作　　者：马国盛 刘英 邓昊[1] 许振宇 何亚柏 阚瑞峰 MA Guosheng;LIU Ying;DENG Hao;XU Zhenyu;HE Yabai;KAN Ruifeng(Anhui Institute of Optics and Fine Mechanics,Hefei Institute of Physical Science,Chinese Academy of Sciences,Hefei 230031,China;University of Science and Technology of China,Hefei 230026,China)

机构地区：[1]中国科学院合肥物质科学研究院安徽光学精密机械研究所,安徽合肥230031 [2]中国科学技术大学,安徽合肥230026

出　　处：《光学精密工程》2022年第19期2305-2312,共8页Optics and Precision Engineering

基　　金：院级重大科研仪器设备研制项目(No.ZDKYYQ20200006);国家自然科学基金资助项目(No.41901081)。

摘　　要：针对温室气体CH_(4)的高灵敏探测需求,提出了高精细度光学反馈腔衰荡光谱技术,研究了光学反馈对腔模信号的影响、系统的灵敏度以及光谱扫描法。在精细度大于100000的V型谐振腔上实现了光学反馈腔衰荡光谱技术,对比了有/无光反馈时腔模信号的差别,验证了光反馈效应可以提高激光到腔的耦合效率。发展了固定腔长的光反馈检测技术,将腔的自由光谱范围FSR用作光谱相对频率标尺,基于HITRAN数据库中两条吸收谱线的绝对波长和测量到的相对位置进行对比分析,得到腔的FSR为0.0042 cm^(-1)。然后,运用allan方差分析了系统的检测能力,测得系统的噪声等效吸收系数为1.1×10^(-10)cm^(-1)Hz^(-1/2),当积分时间为4.7 s时,系统灵敏度为8×10^(-11)cm^(-1)。最后,提出了连续电压扫描的激光器频率控制扫描方法,用1.5×10^(-6)的标气对该方法进行了验证,得到测量精度为6.8×10^(-9)。该方法在仪器工程化方面极具潜力。To meet the requirements of high-sensitivity detection of CH_(4),a greenhouse gas,this study developed a high-finesse optical feedback cavity ring-down spectroscopy technique.The influence of optical feedback on the cavity mode signal,the sensitivity of the system,and the method of spectral scanning were mainly studied.First,the optical feedback cavity ring-down spectroscopy technique was realized on a V-shaped resonator with a finesse greater than 100000,and the difference between the cavity mode signal with and without optical feedback was compared,verifying that the optical feedback effect can improve the coupling between the laser and cavity.Second,an optical feedback detection technique with a fixed cavity length was developed,and the free spectral range(FSR)of the cavity was used as a spectral relative frequency scale.Based on a comparative analysis of the absolute wavelengths and measured relative positions of the two absorption lines in the HITRAN database,the FSR of the cavity was obtained as 0.0042 cm^(-1).Then,the detection capability of the system was analyzed using Allan variance,and the noise equivalent absorption coefficient of the system was measured to be 1.1×10^(-10) cm^(-1) Hz^(-1/2).When the integration time was 4.7 s,the sensitivity of the system was 8×10^(-11)cm^(-1).Finally,a laser frequency-controlled scanning method with continuous voltage scanning was proposed.The method was verified with a standard gas of 1.5×10^(-6) and a measurement accuracy of 6.8×10^(-9).This method has great potential for instrument engineering.

关 键 词：激光光谱 光学反馈 腔衰荡光谱 CH4高灵敏探测 

分 类 号：O433.54[机械工程—光学工程]