Adjustable dual-narrowband nonreciprocal thermal emitter with sign manipulation under low magnetic field

Abstract Dynamic manipulation of the sign and emissivity of nonreciprocal radiation at extremely low magnetic fields while violating Kirchhoff’s law is a significative and challenging problem. In this study, a dual-narrowband nonreciprocal emitter based on magnetophotonic crystal structure capable of achieving dynamic manipulation of emissivity and sign of nonreciprocity is proposed. With a low magnetic field of 0.1 T, the nonreciprocity of proposed emitter exceeds 80%. This study proves that the emissivity and sign of nonreciprocity can be dynamically manipulated by adjusting the rotational angle of the magnetic field without introducing additional active materials. By the study on magnetic field distribution, the dual-narrowband irreversible emission is convinced to originate from the excitation of topological interface states. Additionally, the emitter demonstrates remarkable robustness to the variation of azimuthal angle and thickness of magneto-optical medium. The proposed scheme has potential in the application of wavelength-selective thermophotovoltaic technology.