Characterization of Spatial Light Modulator Based on the Phase in Fourier Domain of the Hologram and Its Applications in Coherent Imaging

Fast and robust calibration method of liquid-crystal spatial light modulator based on polarization multiplexing

We propose a fast and robust method for calibrating Spatial Light Modulators (SLMs) based on polarization phase-shifting interferometry. Our method effectively calibrates the SLM by addressing both the static aberration and nonlinear phase response, utilizing specially designed gray images loaded sequentially onto the SLM. Notably, we introduce a novel kinoform that effectively eliminates the influence of tilt phase shift between two shots of the polarization camera. This results in a highly accurate phase aberration map and phase modulation curve with exceptional stability, making it an ideal method to calibrate the SLM with exceptional efficiency and precision in real applications.

Phase response optimization of a liquid crystal spatial light modulator with partially coherent light

This paper demonstrates a method to determine and calibrate the modulation characteristics of a liquid crystal spatial light modulator (SLM) for on-axis phase response with partially coherent light. A polarimetric approach has been implemented to obtain the phase characterization curve of the SLM. The corrections for phase response errors exhibited by SLM have been incorporated through encoded grayscale patterns to ensure a spatially uniform phase response and a linear relationship between addressed phase and phase delay by SLM. In this approach, corrections can be applied at selective pixels of the SLM's display without altering its gamma curve. Experimental results are presented that verify the feasibility of the proposed approach.

Calibration of a phase-only spatial light modulator for both phase and retardance modulation

Liquid crystal spatial light modulators (SLMs) are usually configured and calibrated for phase modulation. However, as they are variable retarders, they also have application as polarization modulators. We show that conventional phase-only calibrations are insufficient for this purpose, and a separate retardance calibration is needed. To overcome this shortcoming we report a simple Twyman-Green interferometer-based setup to realize SLM phase and retardance calibration. For phase calibration, we identify the non-linear, spatially variant response to the drive voltage of the SLM using fringe analysis and both horizontally and vertically polarized incident light. For retardance calibration, we use incident light polarized at 45° and assess the intensity variation. The methods presented are compatible with in situ calibration of SLMs.