Strong nonreciprocal radiation with topological photonic crystal heterostructure

A nonreciprocal thermal emitter, which consists of a magnetic Weyl semimetal embedded in a topological photonic crystal, is proposed and investigated. An emitter exhibits strong nonreciprocal radiation, which results from the exaction of a topological photonic state between two photonic crystals (PhCs). The underlying physical mechanism of such behaviors is disclosed by illustrating magnetic field intensity distributions at resonances and is further confirmed by investigating the band diagram and the Zak phases of the two PhCs. Aside from that, radiation properties of the proposed emitter remain excellent within wide geometric dimension ranges, which should be interesting for practical fabrication. Finally, considering the actual manufacture and the more intense interest of multi-channel nonreciprocal radiation, the extension of the designed scheme to the multi-channel scheme with more practical structure is also investigated. The results should provide possibility for the development of energy devices and thermal emitters with more engineered function.