Radial-shearing interferometry for phase LC-SLM calibration with a pair of conjugated vortex beams

Spatial light modulators are widely used in various fields such as light field control and beam shaping. It is necessary to calibrate the modulation curve of phase spatial light modulator (SLM) accurately so as to load the pattern correctly. Different from the calibration methods with interference fringes, a group of dynamic petal-like spots with different rotation angles can also be applied to calibrate the modulation curve. The number of petals is generated by a pair of conjugated vortex beams and increases as the increase of vortex topological charge. The calibration accuracy was then greatly improved by weighted algorithm based on the multiple rotated petals. The effectiveness of the proposed SLM calibration method was verified in experiments by four dynamic petals. Compared with the traditional fringe pattern calibration, this method has merit of simple structure, convenient operation and high precision.