Wide-angular-range and high-resolution beam steering by a metasurface-coupled phased array

Optical beam steering has broad applications in lidar, optical communications, optical interconnects, and spatially resolved optical sensors. For high-speed applications, phased-array-based beam-steering methods are favored over mechanical methods, as they are unconstrained by inertia and can inherently operate at a higher speed. However, phased-array systems exhibit a trade off between angular range and beam divergence, making it difficult to achieve both a large steering angle and a narrow beam divergence. Here, we present a beam-steering method based on wave-front shaping through a disorder-engineered metasurface that circumvents this range-resolution trade off. We experimentally demonstrate that, through this technique, one can continuously steer an optical beam within a range of 160 degrees (80 degrees from normal incidence) with an angular resolution of about 0.01 degrees at the cost of beam throughput. (C) 2018 Optical Society of America