Nonreciprocal waveguiding structures for THz region based on InSb

We studied the dispersion relations of the MSPs and their coupling to bulk and waveguide modes in the three types of THz guiding structures, namely InSb/⁠dielectric planar boundary, InSb/⁠air/⁠metal planar waveguide, and symmetric InSb/⁠air/⁠InSb planar waveguide. In particular we demonstrated the possibilities for tuning the central frequencies of the one-⁠way gap and its bandwidth by varying the amplitude of an external magnetic field, the permittivity and thickness of the dielectric guiding layer. Then we evaluated the dispersion relations of all modes supported by the waveguide structures and analyzed their properties in terms of their propagation constants. By using our in-⁠house 2D numerical technique based on the magnetooptic aperiodic rigorous coupled wave analysis (MOaRCWA), we evaluated the relative spectral transmittances in both forward and backward directions of propagation for the structures considered. Our approach deals with the configurations, in which the magnetized sections are sandwiched between the identical structures but without the magnetic field. We believe that this configuration is closer to a structure that might be adopted in envisaged future applications.