Strong nonreciprocal radiation for extreme small incident angle

Abstract

The perfect nonreciprocal radiation effect for extreme small incident angle is studied. The proposed scheme consists of a patterned magneto-optical (MO) material on a continuous MO film backed with a metallic mirror and coated with a metallic film. Perfect emission and extreme small absorption are achieved at resonance, which results in the realization of near-complete nonreciprocal radiation for an incident angle of only 1o. Such phenomenon is attributed to the excitation of guided mode resonance (GMR) in the MO material, which is revealed by investing the magnetic field intensity distribution and confirmed by the impedance matching theory. In addition, the near-complete nonreciprocal radiation performance remains excellent in a wide range of structure parameters, which lowers the costs of production. Last, the scheme is also employed to investigate the possibility for realizing enhanced nonreciprocity with small applied magnetic field and dual-band nonreciprocal radiation. It is believed the proposed scheme is promising in improving the energy conversion in solar cells, thermophotovoltaics as well as thermal routers and thermal diodes.