Closed-loop wavefront calibration of a multi-electrode electrowetting-based tunable microlens

A method to calibrate multi-electrode electrowetting-driven lenses and phase-shifters based on measured wavefront feedback is presented. The aim is to compensate for wavefront errors commonly caused by processing irregularities or surface defects. The wavefront generated by the lens is measured using a Shack-Hartmann wavefront sensor to determine the surface shape. The deviation between the target surface shape is calculated and the electrode voltages are iteratively adjusted. A decentralized control algorithm is implemented which treats the meniscus height at each electrode as a variable with independent feedback control; an adaptive update condition determines which electrodes should be adjusted in each cycle.