Ultra-wideband transmission filter based on guided-mode resonances in two terahertz metasurfaces

This paper reports on a broadband transmission filter that employs the guided mode resonances pertaining to a terahertz metasurface composed of metallic gold disks with a quartz slab. Unlike structures involving conventional metasurfaces, two identical metasurfaces are placed on the upper and lower sides of a thick quartz slab. This structure can excite both even and odd guided mode resonances. The interaction of the two resonances at similar frequencies produces a broadband transmission peak. The sharp spectral feature of each resonance leads to the abrupt degradation of the transmission at the spectral edge, which can enable the development of the filter application. The proposed scheme can facilitate practical applications such as those of broadband filters at a terahertz frequency. (c) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This paper presents a broadband transmission filter based on guided mode resonances in a terahertz metasurface. The filter is composed of metallic gold disks and a quartz slab, with two identical metasurfaces placed on the upper and lower sides of the slab. It can excite both even and odd guided mode resonances, and the interaction of these resonances at similar frequencies results in a broadband transmission peak. The sharp spectral features of each resonance lead to a sudden degradation of transmission at the spectral edge, enabling filter applications.