Sub-Wavelength Passive Optical Isolators Using Photonic Structures Based on Weyl Semimetals

The paper presents the design of sub-wavelength high-performing nonreciprocal optical devices using recently discovered magnetic Weyl semimetals. These passive bulk topological materials exhibit anomalous Hall effect which results in magneto-optical effects that are orders of magnitude higher than those in conventional materials, without the need of any external magnetic bias. Two optical isolators of both Faraday and Voigt geometries are designed. The isolators have dimensions that are reduced by three orders of magnitude compared to conventional magneto-optical configurations. The designed structures demonstrate that the magnetic Weyl semimetals may open up new avenues in photonics for the design of various nonreciprocal components.