Terahertz Ultrahigh-Q Metasurface Enabled by Out-Of-Plane Asymmetry

Owing to strong light confinement ability, the optical resonators are of great interest to the scientific community, however, their optical performances are often limited by the out-of-plane scattering caused by fabrication defects. A physical mechanism known as the Bound States in the Continuum (BIC), can suppress the scattering loss that could lead to improved optical devices. Utilizing the BIC effect, we propose a standard metasurface that can achieve an ultra-high Q factor of 6302. To our knowledge, the achieved Q-factor is the highest achieved by terahertz metasurface so far. Owing to strong light confinement ability, the metasurface is highly sensitive to its surrounding environment.