Surface mode at isotropic–uniaxial and isotropic–biaxial interfaces

TLDR: The surface mode that propagates along the interface between isotropic and uniaxial materials is quantitatively characterized in terms of (1) the range of crystallographic orientations for which the mode propagates, (2) its propagation constant β, and (3) its field profiles as mentioned in this paper.

Abstract: The surface mode that propagates along the interface between isotropic and uniaxial materials, as first suggested by M. I. D’Yakonov [Sov. Phys. JETP67, 714 (1988)], is quantitatively characterized in terms of (1) the range of crystallographic orientations for which the mode propagates, (2) its propagation constant β, and (3) its field profiles. Previous studies have considered only uniaxial materials whose optic axis is in the plane of the interface. We show that a surface mode can also propagate along the interface between isotropic and arbitrarily oriented uniaxial or biaxial materials. This mode is also quantitatively characterized. For the biaxial material oriented so that its optic axes lie in the plane of the interface, it is shown that this surface mode is guided over a greater range of propagation directions and that the light is confined more tightly than for any isotropic–uniaxial interface of comparable birefringence. In addition, it is shown that the surface modes that occur at isotropic–uniaxial interfaces combine to form a new type of hybrid mode in uniaxial slab waveguides (two interfaces). The resulting modes differ from conventional slab waveguide modes in that (1) they are composed entirely of inhomogeneous waves and (2) at most two of these modes can exist regardless of the waveguide thickness.