Dyakonov surface waveguide modes in ring resonators.

We theoretically predict and numerically simulate the existence of Dyakonov surface waveguide modes (DSWMs) at the interface between two anisotropic uniaxial ring resonators. The spectral and polarization properties of DSWM for different values of ring radius are explored. In addition, we consider a structure in which a gap made of anisotropic material is added between two ring structures. It was revealed that the gap size strongly affects both chirality density and the degree of circular polarization of the modes. Due to this, interfacial ring resonators have potential in chiral molecular polaritonics as a platform for optical sensing of chiral organic molecules.