A high Resolution and Accuracy Phase-only Spatial Light Modulator

High resolution and accuracy phase modulation could help to improve the diffraction efficiency of spatial light modulator. For spatial light modulator with analog driving pixels, the phase accuracy is mainly decided by the DAC design. The conventional circuit design method to improve the DAC accuracy is using a large chip area or using expensive advanced manufacturing technology. In this paper, a calibration method with both analog and digital algorithm is presented. By adding digital calibration and improving the frame frequency, the liquid crystal response characteristic is improved without changing the on chip DAC design. An 8 bit DAC LCoS panel is used for verification. The experiment result shows, the phase error is reduced from 1.49% to 0.44%, and the diffraction efficiency is improved from 72% to 75%. And a holography picture is projected to verify the effect.