Refractive opto-fluidic wavefront modulator with electrostatic push-pull actuation

Two-dimensional spatial wavefront modulation in real-time is an essential tool for applications such as adaptive optics and laser beam shaping. Micro-mirror-based MEMS wavefront modulators have led to a major reduction in the cost of practical wavefront modulation, but the system complexities due to their reflective operation are still prohibitive. To address this issue, we demonstrate here a highly-miniaturized electrostatically actuated optofluidic transmissive phase modulator capable of positive or negative phase shifting through the use of hydromechanical coupling. The approach is based on a unique push-pull electrostatic actuation concept that exploits the inherent liquid-mechanical coupling in the design and is free of polarization and diffraction effects. This optofluidic phase modulator is able to correct aberrations up to 5th radial Zernike polynomial modes with high fidelity and, by use of sensorless wavefront estimation algorithms, allows for the realization of a completely in-line adaptive optics system.