Two-Shot Calibration Method for Phase-Only Spatial Light Modulators with Generalized Spatial Differentiator

For phase-only spatial light modulators (SLMs), it is necessary to calibrate phase-response curves in various applications with light wavefront shaping. Here we develop a method to calibrate the global phase-response curve, based on the generalized optical spatial differentiation. We show that by only setting two specific profiles in SLM and analyzing the light reflected by a planar interface under cross-polarization conditions, the phase delay can be evaluated from two shots of intensity images. In comparison with conventional interferometric or diffractive approaches, we experimentally demonstrate that the present method enables in situ calibration and takes advantages of simple process and high stability. Besides, the method can also be used to calibrate the phase-response curve of each single pixel.