Gyrotropic Confinement in Gyromagnetic Medium-Encased Dielectric Structures

We use photonic spin and isofrequency curves to investigate the role of strong gyrotropy in ferrite in suppressing the propagation of a particular mode leading to wave evanescence in ferrite. We use this phenomenon to design a novel ferrite-encased waveguide. Our proposed waveguiding structure shows strong non-reciprocal wave propagation characteristics and can be used for various non-reciprocal applications. This work provides important insights into using gyrotropic materials for realizing miniaturized cutoff-less and non-reciprocal waveguides.