A multi-band nonreciprocal thermal emitter involving a Weyl semimetal with a Thue-Morse multilayer.

Abstract

The giant enhancement of multi-band nonreciprocal radiation based on the Weyl semimetal-dielectric spacer-Thue-Morse multilayer-metallic mirror structure, is investigated. As an illustration, a novel dual-band nonreciprocal thermal emitter based on the proposed scheme is designed and studied. The results show that two pairs of nonoverlapping absorptivity and emissivity spectra could be realized, which results in the realization of strong dual-band nonreciprocal radiation. The physical origin behind this phenomenon is revealed by the amplitude distribution of the magnetic field and confirmed by impedance matching theory. The dependence of the nonreciprocal radiation properties on the incident angle and the structure dimensions is investigated, and it is shown that the nonreciprocal performance remains stable in a large range of dimensions, which lowers the costs of fabrication. In addition, a multi-band nonreciprocal thermal emitter with a band number larger than two can be easily achieved by increasing the generation of the Thue-Morse multilayer. It is believed that the proposed scheme will promote the development of novel multi-band nonreciprocal thermal emitters.