Common-path and phase-shift interferometer for length measurement

摘要

Polarized laser phase shifting method is adopted in this single frequency laser interferometer to solve "zero drift" of laser intensity in conventional single frequency laser interferometer. The measurement stability and repeatability are improved by means of common optical path arrangement. The resolution power of the interferometer is improved by using optical path difference doubling technique. In the experiment the main factors that affect the length measurement precision are analyzed and calculated. Results obtained are shown.