Device and method for measuring phase modulation characteristic of spatial light modulator

The invention discloses a device and method for measuring the phase modulation characteristic of a spatial light modulator. The device comprises a laser and a spatial light modulator. A beam-expandingmicroscopic objective, a collimating lens, a polarizer for transforming the light in any polarization state into linear polarized light, and a spectroscope are successively arranged between the laserand the spatial light modulator. The spectroscope is configured to pass the light passing through the polarizer and reflect the light beam from the spatial light modulator. The spatial light modulator is connected with a computer to load a combination pattern grayscale map. The computer is connected with a CCD camera for acquiring interference fringe patterns. The device and method use the spatial light modulator to load the combination pattern grayscale map, use a liquid crystal blazed grating to enhance the contrast of the fringes. The self-interference method reduces the influence of the air turbulence. The quality