Topology Optimization Enables High-<i>Q</i> Metasurface for Color Selectivity
Huan‐Teng Su, Lu-Yun Wang, Chih‐Yao Hsu, Yun-Chien Wu, Chang-Yi Lin, Shu-Ming Chang, Yao‐Wei Huang
Abstract
High Resolution Image Download MS PowerPoint Slide Nonlocal metasurfaces, exemplified by resonant waveguide gratings (RWGs), spatially and angularly configure optical wavefronts through narrow-band resonant modes, unlike the broad-band and broad-angle responses of local metasurfaces. However, forward design techniques for RWGs remain constrained at lower efficiency. Here, we present a topology-optimized metasurface resonant waveguide grating (MRWG) composed of titanium dioxide on a glass substrate capable of operating simultaneously at red, yellow, green, and blue wavelengths. Through adjoint-based topology optimization, while considering nonlocal effects, we significantly enhance its diffraction efficiency, achieving numerical efficiencies up to 78% and Q -factors as high as 1362. Experimentally, we demonstrated efficiencies of up to 59% with a Q -factor of 93. Additionally, we applied our topology-optimized metasurface to color selectivity, producing vivid colors at 4 narrow-band wavelengths. Our investigation represents a significant advancement in metasurface technology, with potential applications in see-through optical combiners and augmented reality platforms.