TE-three/TM-four channels nonreciprocal thermal radiation and mechanism by Ge/InAs metamaterials

Abstract

Most studies on nonreciprocal thermal radiation have been conducted under TM polarization and at larger angles of incidence, which limits the performance and application scope of nonreciprocal radiation. Additionally, multiband nonreciprocal radiation is essential for applications in energy conversion and thermal management. This paper introduces an innovative two-dimensional nonreciprocal thermal emitter that achieves three channels under TE polarization and four channels under TM polarization at an incidence angle of 4.7° with only a 0.8 T magnetic field. The emitter consists of a germanium-metal hollow array, a magneto-optical material layer (InAs), and a metallic reflective layer (Ag). Utilizing rigorous coupled-wave analysis (RCWA) in conjunction with coupled mode theory (CMT), we investigated the characteristics of the nonreciprocal thermal emitter and conducted a detailed analysis of its electromagnetic field energy distribution to elucidate the underlying physical phenomena of nonreciprocal thermal radiation. The presented small-angle, dual-polarization multichannel nonreciprocal thermal emitter holds significant potential for applications in energy conversion and thermal management, providing a novel approach for achieving multichannel nonreciprocity under dual polarizations.