Nonlinear error of grating measurement system caused by non-ideal characteristics of waveplates

To reduce nonlinear errors in grating measurement systems, it is essential to thoroughly understand how non-ideal waveplates contribute to these errors. Based on Jones matrix theory, an error analysis model for waveplates was established, and nonlinear error models caused by waveplate phase retardation and installation errors were derived. Simulation results indicate that angular misalignments of waveplates distort the trajectories of Lissajous diagrams, and the nonlinear error increases proportionally with the angular errors. Additionally, the phase retardation errors of waveplates have a relatively minor effect on the system when the errors are small; however, once the phase retardation error exceeds a certain threshold, the nonlinear error increases significantly.