Reconfigurable Si-based Active Metasurface with Ultra Low Loss and Crosstalk for LiDAR

Recently, we have demonstrated a solid-state spatial light modulator (SLM) with a plasmonic antenna array, and this has attracted substantial interest due to its excellent modulation performance and potential use in beam shaping. Despite of its huge advantage - independently controlled magnitude and phase of light that allows versatile optical scan -, its very low reflection efficiency makes it unsuitable for real-world applications. In this paper, we have demonstrated a Si-based SLM design using asymmetric resonator composed of p-i-n diode structure and distributed Bragg reflector. We obtained experimentally the world-record reflection efficiency over 50% and the phase modulation of 300°. We also measured the maximum side-mode-suppression-ratio of 10.53 dB, also the world record, with a clean far-field pattern, excellent SNR, and steering capability.