腔长变化对连续波腔衰荡技术测量的影响

Influence of cavity length change on measurement of CW cavity ring-down

为了阐明腔长变化对测量的影响,在考虑入射光源光谱线宽的情况下,采用腔衰荡法和多光束干涉等有关理论,就两种极限情况下腔长变化对连续波腔衰荡法测量的影响进行了分析和数值模拟,并据此讨论了一般情况下腔长变化给测量带来的影响。分析表明,腔长变化主要使衰荡腔谐振频率变得不稳定,从而使得衰荡腔出射光功率及其衰荡特征发生变化,进而给测量带来严重误差,这将为分析该技术测量误差来源以及提高其测量精度提供理论指导。

In order to clarify the impact of cavity length change on measurement, taking the laser＇s line-width into account, the influence of cavity length change on the measurement of cavity ring-down in two limiting cases was analyzed and simulated by using cavity ring-down and muhiple-beam interferometry theory, hereby the general cases were discussed. Analyses showed the instability chiefly changed resonant frequency of ring-down cavity, then varied the emergent light power and the feature of ring-down signal, which shouled bring serious measurement error. All of these will provide theory direction to measurement error analysis and improve measurement accuracy.