Calibration of liquid crystal spatial light modulators by using the double-phase method

In this manuscript, two diffraction-based methods for calibrating liquid crystal spatial light modulators are demonstrated theoretically and experimentally. They rely on the coherent interference of two uniform waves whose complex functions are encoded in a single-phase diffractive optical element by using the double-phase method. The interference pattern, recorded in the output plane of a spatially filtered 4 f optical imaging system, allows calibration curves to be determined by post-processing. With these methods, both global and local phase calibrations can be performed, allowing inhomogeneous phase responses in liquid crystal displays to be evaluated and tested in a variety of experimental scenarios, such as multiwavelength illumination or varying incidence angles.