Multi-region phase response calibration of SLM based on a Shack–Hartmann wavefront sensor

In order to accurately measure the phase modulation capability of the spatial light modulator (SLM) and improve its performance in optical applications, a multi-region phase response calibration scheme of SLM based on the Shack–Hartmann wavefront sensor (SHWS) is proposed. This scheme addresses the nonlinear sampling issue of the liquid crystals in different sampling areas on the SLM. By loading and shifting dual sine phase patterns, continuous variations of grayscale values in the same region on the SLM screen were achieved, with the corresponding wavefront data recorded by the SHWS after each grayscale change. Matrix calculations were performed in MATLAB to obtain the corresponding phase modulation curve. Subsequently, the multi-zone phase modulation characteristics of the SLM were measured. Following the nonlinear calibration of phase modulation in each zone of the SLM, the intrinsic wavefront distortion (WFD) of the SLM was measured using the SHWS in conjunction with the calibration results and compensated for. The compensated WFD of the SLM is reduced from 0.7976 λ to 0.3415 λ ( λ =632.8nm), and in the verification experiment, the focused spots’ quality was greatly improved with the calibrated SLM. The experimental results proved the availability of the multi-region phase response calibration scheme. Compared to conventional methods, this approach demonstrates simplicity, real-time performance, and robustness.