激光衰荡测量中腔内能量动态过程分析研究

Analysis of intracavity energy dynamic processes in laser cavity ring-down measurement

从激光衰荡中衰荡腔内能量的动态变化出发,考察了电流调制腔衰荡的频率匹配过程,分析了激光波长扫描速率对光强注入变化的影响,进而解释了光关断后衰荡曲线出现过充畸变的原因,研究了不同充光时间下检测精度的变化规律。实验考察了不同触发阈值和延迟时间等参数设置下激光衰荡过程,发现随着触发阈值的增加,测量精度和灵敏度提升,但衰荡检测频率明显下降,因此触发阈值的设置应同时兼顾测量精度和测量频率要求。此外,延迟时间的增加会影响测量幅值的稳定,但可获得较高的测量精度和衰荡时间。实验中当延迟时间为400 ns时,测量幅值与测量精度达到平衡,此时衰荡时间为39.1403μs,测量精度为0.0162。

In this paper,based on the dynamic change of energy in the ring-down cavity in the laser ring-down,the frequency matching process of the current-modulated cavity ring-down is investigated,and the influence of the laser wavelength scanning rate on the change of light intensity injection is analyzed,then the reason for the overcharge distortion of the decay curve after the light is turned off is explained,and the change law of detection accuracy under different light charging times is studied.The laser ring-down process under different trigger threshold and delay time parameter is investigated experimentally.It is found that as the trigger threshold increases,the measurement accuracy and sensitivity increase,but the ring-down detection frequency is significantly reduced,so the trigger threshold setting should take into account both the measurement accuracy and measurement frequency requirements.In addition,the increase of the delay time affects the stability of the measurement amplitude,but higher measurement accuracy and ring-down time can be obtained.In the experiment,when the delay time is 400 ns,the measurement amplitude and measurement accuracy reach a balance,at which time,the ring-down time is 39.1403μs,and the measurement accuracy is 0.0162.