A layered metastructure based on brewster angle for Janus ultra-wideband tunable directional thermal radiation

Abstract

In this proposal, we introduce a Janus layered metastructure (JLM) composed of three distinct structures. The first and third structures (S1 and S3) are designed based on Brewster and Bragg reflection laws, which enable the selection of a specific incident angle of electromagnetic waves (EMWs) by adjusting the refractive indices of the materials. By matching the thickness of the dielectric layer to the optical wavelength, S1, and S3 operate across the 30–300 μm band, achieving angle selection (AS) of EMWs in the THz band. The second structure (S2) consists of a single layer of graphene and SiO2 arranged in quasi-periodic sequences, which absorbs EMWs in the THz band and achieves broadband absorption without angle sensitivity. By combining the characteristics of these three structures, we achieve a broadband directional thermal radiation covering the 30–300 μm band. Additionally, the adjustability of the AS of S1 and S3 and the absorption effect of S2 enable Janus ultra-wideband tunable directional thermal radiation at large angles depending on the specific needs.