Modeling the nonlinearity of polarizing beam splitters in nano-displacement measurement of laser encoder using Jones matrix analysis

Abstract

In this paper, nonlinearity error of a laser encoder is modeled by using the Jones matrix analysis. In the nano-metrology system we suppose that polarizing beam splitters are imperfect. The intensity of interference signals on photodetectors are obtained and simulated by MATLAB software. The nano-displacement of scale grating is simulated by Arctangent method. We show that maximum nonlinearity error phase is equal to 0.07166 rad when the pitch of scale grating and wavelength of the laser are 1 μm and 685 nm, respectively.