Dynamic manipulation of magnitude and sign of nonreciprocal emitter by rotation angle of magnetic field

Abstract Dynamic manipulation of the magnitude and sign of nonreciprocal radiation is widely used in heat circulator, nonreciprocal solar cell, and nonreciprocal radiative cooling device. However, the effect of a magnetic field not being perfectly perpendicular to the incident plane on nonreciprocity remains unclear at present. To address this fundamental and critical issue, the effect of the magnetic field rotation angle on the nonreciprocal emitter with magnetophotonic crystal structures is comprehensively analyzed. The magnitude and sign of nonreciprocity can be dynamically manipulated via the rotation angle. The sign of nonreciprocity would be changed near the rotation angle of π /2. The devices exhibiting reciprocal behavior carry the rotation angle of π /2. Moreover, the nonreciprocal absorption and emission spectra can be dynamically manipulated by the rotation angle without additional introduction of graphene or phase change materials. The strong irreversible radiation is attributed to the optical Tamm plasmon polaritons at the interface between the photonic crystal and the metal. Coupled mode theory is adopted to elaborate the potential physical mechanism and further verify the validity of calculations. The generalized results that cover the case of multi-band nonreciprocal radiation prove the design flexibility and reliability. This work is believed to be helpful to improve the energy conversion efficiency of wavelength-selective thermophotovoltaic systems.