Parametric investigation of prism-coupled excitation of Dyakonov-Tamm waves

In order to pave the way for the yet-to-be reported experimental observation of the Dyakonov-Tamm wave, the excitation of this surface wave in a prism-coupled configuration was theoretically investigated when one partnering dielectric material is isotropic and homogeneous while the other is a chiral sculptured thin film (CSTF). The excitation of a Dyakonov-Tamm wave in the prism-coupled configuration was identified by those peaks in the plots of the absorptance versus the angle of incidence that were independent of the thicknesses of both partnering materials (beyond some thresholds) and the polarization state of the incident plane wave. The results of the prismcoupled configuration were successfully correlated with the underlying canonical boundary-value problem. An increase in either the structural period or the average vapor flux angle of the CSTF results in a larger angle of incidence for experimental excitation, whereas an increase in an offset angle results in a decrease of that angle. An increase in the bulk refractive index of the material from which the CSTF is fabricated is likely to increase the angle of incidence for experimental observation. It is highly preferable for the CSTF to be an integral number of periods in thickness, and that number does not have to be large.