  In order to ascertain conditions for surface-wave propagation guided by the
planar interface of an isotropic dielectric material and a sculptured nematic
thin film (SNTF) with periodic nonhomogeneity, we formulated a boundary-value
problem, obtained a dispersion equation therefrom, and numerically solved it.
The surface waves obtained are Dyakonov-Tamm waves. The angular domain formed
by the directions of propagation of the Dyakonov--Tamm waves can be very wide
(even as wide as to allow propagation in every direction in the interface
plane), because of the periodic nonhomogeneity of the SNTF. A search for
Dyakonov-Tamm waves is, at the present time, the most promising route to take
for experimental verification of surface-wave propagation guided by the
interface of two dielectric materials, at least one of which is anisotropic.
That would also assist in realizing the potential of such surface waves for
optical sensing of various types of analytes infiltrating one or both of the
two dielectric materials.
