High Q Asymmetrical Terahertz Metasurface For Frequency Selective Applications

Optical resonators are of significant interest due to their strong light confinement ability. However, the resonator performance is often limited by the out-of-plane scattering caused by fabrication defects. A physical mechanism known as bound states in the continuum can potentially suppress the scattering, leading to improved optical devices. Using the concept, here we propose a standard metasurface having two elliptical silicon (Si) blocks to create out-of-plane asymmetry. The device parameters are optimized by the Genetic Algorithm (GA). Fabrication of the device is carried out following standard fabrication methods. The experimental outcome shows that the metasurface can achieve a high Q factor of 236 which is in good agreement with the simulation. Owing to its strong light confinement ability the metasurface can be used as a frequency selective device, filter, and biochemical sensor.