Metasurface-enabled circular light propagation for ultra-fast and efficient photodetection

We present a novel photodetector that involves the metasurface-induced scattering of a vertically oriented photon beam into a circularly oriented directional and guided light propagation, resulting in enhanced detection efficiency in an ultra-thin photoabsorption layer. The higher absorption efficiency is enabled by an enhanced photon density of states while substantially reducing the optical group velocity of light and extending the photon material interaction time compared to traditional semiconductor photodetectors without an integrated metasurface. Such detectors with a very thin absorption layer can enable high-efficiency and high-speed photodetectors needed in ultrafast computer networks, data communication, imaging and quantum systems.