实时三光束横向剪切干涉仪

The Real-time Three-beam Lateral Shearing Interferometer

对三光束实时横向剪切干涉仪进行了全面深入的分析，导出了其位相测量原理及误差公式。分析表明三光束干涉相叠加产生的信号具有二倍频分量，与通常双光束干涉有根本区别，但是适当地使用这个信号并不会导致测相原理的复杂化，相反，还会降低测量方法的理论误差。

An analysis is performed to a three-beam real-time lateral shearing interferomter with which its principle of phase measurement and error formula are derived. The analysis shows that the signal includes double-frequency component when three-beam lights interfere. It is very different from the common double-beam interference, but the doublefrequency does not make the calculation of phase measurement complex if used properly,On the contray it decreases the theoretical error.