Metasurface-based depth sensing and topology optimized high-Q metasurfaces

In this invited talk, I will present our recent developments and applications of dielectric metasurfaces in depth sensing, facial recognition, and topology-optimized high-Q metasurfaces. In the first part, we demonstrate a commercially compatible metasurface-based dot projector that integrates a metasurface hologram with photonic crystal surfaceemitting laser (PCSEL). Compared to conventional dot projectors, our approach achieves a 233-fold reduction in area, a 10.8-fold decrease in power consumption, a 1.43-fold increase in the number of near-infrared dots, and a twofold expansion in field-of-view (FOV). In the second part, we introduce a novel topology-optimized nonlocal metasurface that operates simultaneously at red, yellow, green, and blue wavelengths. Unlike local metasurfaces with broadband and broad-angle responses, nonlocal metasurfaces, exemplified by resonant waveguide gratings (RWGs), spatially and angularly configure optical wavefronts through narrow-band resonant modes. Our metasurface resonant waveguide grating (MRWG), designed using higher efficiency techniques compared to traditional RWGs, demonstrates experimental efficiencies up to 59% with a quality factor (Q-factor) of 93. It is also applied to achieve color selectivity, producing vivid colors at four narrow-band wavelengths with narrow-angle responses.