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.

• 摘要基于谐振腔失调灵敏度参量随腔长的变化关系，提出了一种衰荡腔，它是由共焦腔将腔长缩短为原来的0.；73得到的稳定腔。