On Dyakonov-Voigt surface waves guided by the planar interface of dissipative materials
Dyakonov-Voigt (DV) surface waves guided by the planar interface of (i) material $A$ which is a uniaxial dielectric material specified by a relative permittivity dyadic with eigenvalues $ε^s_A$ and $ε^t_A$, and (ii) material $B$ which is an isotropic dielectric material with relative permittivity $ε_B$, were numerically investigated by solving the corresponding canonical boundary-value problem. The two partnering materials are generally dissipative, with the optic axis of material $A$ being inclined at the angle $χ\in [ 0^\circ, 90^\circ ]$ relative to the interface plane. No solutions of the dispersion equation for DV surface waves exist when $χ=90^\circ$. Also, no solutions exist for $χ\in ( 0^\circ, 90^\circ )$, when both partnering materials are nondissipative. For $χ\in [ 0 ^\circ, 90^\circ )$, the degree of dissipation of material $A$ has a profound effect on the phase speeds, propagation lengths, and penetration depths of the DV surface waves. For mid-range values of $χ$, DV surface waves with negative phase velocities were found. For fixed values of $ε^s_A$ and $ε^t_A$ in the upper-half-complex plane, DV surface-wave propagation is only possible for large values of $χ$ when $| ε_B|$ is very small.