Li Zhixin, Ma Weiguang, Fu Xiaofang, Tan Wei, Zhao Gang, Dong Lei, Zhang Lei, Yin Wangbao, Jia Suotang
State Key Laboratory of Quantum Optics and Quantum Optics Devices, Laser Spectroscopy Laboratory, Shanxi University, Taiyuan 030006, China.
Opt Express. 2013 Jul 29;21(15):17961-71. doi: 10.1364/OE.21.017961.
A new type of continuous-wave cavity ringdown spectrometer based on the control of cavity reflection for trace gas detection was designed and evaluated. The technique separated the acquisitions of the ringdown event and the trigger signal to optical switch by detecting the cavity reflection and transmission, respectively. A detailed description of the time sequence of the measurement process was presented. In order to avoid the wrong extraction of ringdown time encountered accidentally in fitting procedure, the laser frequency and cavity length were scanned synchronously. Based on the statistical analysis of measured ringdown times, the frequency normalized minimum detectable absorption in the reflection control mode was 1.7 × 10(-9)cm(-1)Hz(-1/2), which was 5.4 times smaller than that in the transmission control mode. However the signal-to-noise ratio of the absorption spectrum was only 3 times improved since the etalon effect existed. Finally, the peak absorption coefficients of the C(2)H(2) transition near 1530.9nm under different pressures showed a good agreement with the theoretical values.
设计并评估了一种基于腔反射控制的新型连续波腔衰荡光谱仪用于痕量气体检测。该技术通过分别检测腔反射和透射，将衰荡事件的采集与光开关的触发信号分离。给出了测量过程时间序列的详细描述。为避免在拟合过程中偶然遇到的衰荡时间错误提取，对激光频率和腔长进行同步扫描。基于对测量衰荡时间的统计分析，反射控制模式下频率归一化的最小可检测吸收为1.7×10(-9)cm(-1)Hz(-1/2)，比透射控制模式下小5.4倍。然而，由于存在标准具效应，吸收光谱的信噪比仅提高了3倍。最后，不同压力下1530.9nm附近C(2)H(2)跃迁的峰值吸收系数与理论值吻合良好。
