Tunable optical metasurfaces for continuous beam steering and dynamic focusing

In this invited talk, we present our recent results on a coherently controlled, beam-steering metasurface. The metasurface consists an array of silicon nanopillars on top of a glass substrate. The optical response of individual pillars can be tuned by controlling the relative phase and strength of two incident light beams. The collective response of all the pillars results in a tunable phase gradient across the metasurface, which dictates the direction of the output laser beam. Based on numerical simulation, the direction is tuned within a range of approximately 10 degrees