连续波腔衰荡技术原理推导及实验研究

基于无源腔的Q值定义,根据能量守恒原理,对连续波腔衰荡技术测量原理进行了推导,并基于多光束干涉理论,就入射光关断时间对腔出射光强信号衰荡线形及测量结果的影响进行了数值模拟和分析,分析表明：入射光的关断时间很大程度上决定着腔出射光功率信号的衰减线形,如果要消除入射光关断时间对测量结果的影响,入射光关断必须小于腔衰荡时间的1%。根据理论分析要求建立了一套测量系统,并对腔损耗约为50ppm的低损无源腔进行了实际测量,实验结果的分析显示,该测量系统测量误差约为0．15ppm。

Theoretical derivation and experimental research of continuous-wave cavity ring-down technology

Based on the definition of passive cavity's Q value,measurement principles of continuous-wave cavity ring-down technology was deduced from the energy conservation law,then the impacts of incident light's shutoff time on measuring result were nu- merically simulated and analyzed according to multi-beam interference theory.The results show that the decay feature of emergent light power is determined by the shut-off time of incident light,which should be less than 1% of cavity decay time for eliminating its impact on measuring result.Finally,a set of measurement systems was established and a passive cavity whose loss is about 50ppm has been measured,the experimental results show that the measurement error of system is about 0.15ppm.