High-precision displacement measurement method based on the interference of conjugate rotationally symmetric...

Existing vortex beam interferometric measurement methods are constrained by the linear spiral phase of conventional vortex beams, resulting in a fixed linear relationship between displacement and rotation angle, which limits further improvement of measurement accuracy. In this paper, rotationally symmetric power-exponent phase vortex beams are introduced. Based on their nonlinear phase distribution, a nonlinear correlation between displacement and rotation angle is established, and angular inhomogeneous modulation of light intensity is realized to amplify the rotation angle within a specific interval. By tuning only the power exponent, the proposed method achieves angular amplification without increasing optical system complexity, and significantly improves the micro-displacement measurement accuracy and system stability compared with traditional vortex interferometry.