The experiments show that the optical path of Plight coincides with that of Slight,which is self-adaptive to the disturbance of the air index or any others and has high stability.

• 在整个光路中，P光与S光完全重合，满足共光路原则，对空气折射率和其它各种扰动具有很好的自适应性，检测稳定性好；