Multi-band and wide-angle robust nonreciprocal thermal radiation based on graphene grating/InAs/SiC heterostructures

Abstract Nonreciprocal thermal radiation (NTR), which enables the violation of Kirchhoff’s law by breaking Lorentz reciprocity, holds significant potential for advanced thermal management and energy harvesting applications. In this study, a graphene grating/InAs/SiC hybrid heterostructure on an Ag substrate is proposed to achieve multi-band, strong, and angle robust nonreciprocity. Theoretical calculations utilizing the rigorous coupled-wave analysis method under TE polarization wave demonstrate that the proposed emitter exhibits four distinct radiation peaks under an external magnetic field of 3 T, two of which achieve nonreciprocity exceeding 90%. The spectral positions and intensities of these peaks can be actively tuned by modulating the external magnetic field and the Fermi level of the graphene. Crucially, this NTR device demonstrates exceptional robustness against angular variations, maintaining high nonreciprocity across a broad range of incidence angles from 0° to 70° and azimuthal angles from 60° to 120°. This angular stability is attributed to the enhanced electromagnetic field confinement and relaxed phase-matching conditions facilitated by the coupling between localized surface plasmons in the graphene grating and optical modes in the InAs and SiC layers. These findings offer a promising design strategy for developing efficient, tunable, and wide-angle NTR emitters.