  A surface electromagnetic wave called the Dyakonov-Tamm wave has been
theoretically predicted to exist at the interface of two dielectric materials
at least one of which is both anisotropic and periodically nonhomogeneous. For
experimental confirmation, a prism-coupled configuration was used to excite the
Dyakonov-Tamm wave guided by the interface of a dense thin film of magnesium
fluoride and a chiral sculptured thin film of zinc selenide. The excitation was
indicated by a reflection dip (with respect to the angle of incidence in the
prism-coupled configuration) that is independent of the polarization state of
the incident light as well as the thicknesses of both partnering materials
beyond some thresholds. Applications to optical sensing and long-range on-chip
communication are expected.
