High-Q Metasurface with 2D Topology Optimization for Color Selection

Chih-Yao Hsu^1*, Huan-Teng Su¹, Yao-Wei Huang¹

¹Department of photonics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:Chih-Yao Hsu, email:z082500.ee12@nycu.edu.tw

Nonlocal metasurfaces with high-Q spectral phenomenon were mostly achieved by forward design. Our recent development of one-dimensional high-Q metasurface improved the efficiency. However, the optimization was restricted by narrow-band selection because of the lower degree of freedom in geometry. We expand this to two-dimension (2D) optimization, allowing greater design freedom. Manipulating momentum along 2D with non-symmetric gratings, we attained a Q-factor of up to 2657 in red light. Furthermore, 2D metasurface suppresses yellow light which is limited in 1D metasurface. This achievement overcomes traditional nonlocal metasurfaces constraints in wavelength and enables Q-factor to go beyond conventional limits.

Keywords: Resonant waveguide grating, Topology optimization, Metasurface, Nonlocal, High-Q