In recent years, the value of research in the field of nonreciprocal energy radiation has been increasing. However, at present, the study of nonreciprocal structures with polarization independence and small-angle incidence is still to be further researched, which is what this paper focuses on. In this paper, a device consisting of a two-dimensional grating, a magneto-optical material layer, and a metal plate is proposed, which can realize polarization-independent nonreciprocity. Two pairs of complementary nonreciprocal peaks can be obtained for TE and TM polarizations in the wavelength range of 10.3–10.8 μm, with nonreciprocal efficiencies exceeding 89% and up to 92%. Moreover, at the wavelengths of 10.696 and 10.760 μm, the polarization-independent nonreciprocal phenomenon can be formed; meanwhile, the efficiency exceeds 87.5% and reaches up to 92%. At polarization-independent nonreciprocal peaks where resonance occurs, through careful analysis of the distribution of electromagnetic fields and the use of coupled mode theory, we have discovered the physical mechanisms that form nonreciprocal phenomena and verified the data. The results in this paper provide more practical ideas for the research and development of nonreciprocal energy radiation devices.
Lin et al. (Fri,) studied this question.