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.