Incremental phase measurement of conoscopic holography measurement system

Contrast to gain phase information from the conoscopoc hologram, detecting laser intensity of conoscopic hologram by non-contact measurement based on conoscopic holography is influenced by laser fluctuation easily. To eliminate the conjugate image by phase-shifting devive, phase-shifting error is also included in the intensity of conoscopic hologram. On the basis of theoretic analysis and experiments, the method of incremental phase measurement is proposed, which makes up the shortage of laser intensity measurement and improves measurement precision. This is important to optimize system design and enhance the accuracy of system.