衰荡光腔中腔镜倾斜分析

分析了衰荡腔中腔镜倾斜产生的腔长失调和单程损耗因子变化,根据失调腔矩阵分析方法并参照实验参数,建立了腔镜角度失调下反射率测量的理论模型.利用该模型,模拟了不同腔镜倾斜量下的衰荡信号波形,分析了波形变化的原因,研究了测量精度与腔镜倾斜量的关系.分析表明,腔镜微小倾斜产生的衍射损耗的变化可以忽略,但导致的腔长变化和衰荡光斑漂移,会限制测量的精度.将衰荡波形的变化用于腔镜角度的精确调节中,可以提高该测量精度.

Analysis of cavity mirrors' tilt in ring-down cavity

The change of the cavity length and single-pass loss in ring-down cavity is deduced from the misalignment angle of cavity mirrors.Based on the matrix method of misalignment resonator and experimental parameters,a theoretical model is proposed to simulate measurement of reflectivity for cavity mirrors' tilt in ring-down cavity.Applying this model,the waveform of ring-down signal can be simulated and its change reason is analyzed.Then the relation between measurement precision and cavity mirrors' tilt is studied.The analysis shows that the measurement precision drops rapidly with length misadjustment and spot offset brought by cavity mirrors' tilt.To improve measurement precision,it is suggested that ring-down signal on the oscillograph should be applied to adjust the cavity mirror.