Choosing cavity parameters in cavity ring-down method

Based on the change of misalignment sensitivity with the length of cavity, a kind of ring-down cavity is put forward, which is stable resonator, and its cavity length is 0.73 times as that of confocal cavity. According to propagation equation of Gaussian beam and matrix of misadjust resonator, as well as principle of cavity ring-down method and data processing of fitting, a physical model of reflectivity measuring is set up for misadjustment of cavity length or angle of titled cavity mirrors. Applying this model, the influence of minute cavity misadjustment on measured reflectivity of cavity mirrors in the stable resonator is analyzed, which is compared to that in confocal resonator. Used as ring-down cavity, this stable resonator has, firstly, more influence of misalignment of cavity mirr