Synoptic view of Dyakonov–Tamm waves localized to the planar interface of two chiral sculptured thin films

Abstract

The Dyakonov-Tamm wave combines the features of the Dyakonov wave and the Tamm electronic state. Dyakonov-Tamm waves guided by the planar interface of two dissimilar chiral sculptured thin films (STFs) were systematically examined. The interfaces result from the chiral STFs being dissimilar in (a) orientation about the helical axis, (b) structural handedness, (c) structural period, (d) vapor incidence angle, (e) material, or (f) various combinations thereof. A boundary-value problem for the propagation of Dyakonov-Tamm waves was formulated and numerically solved. Up to three physical solutions were obtained for any specific combination of constitutive properties of the two chiral STFs. Each solution indicates the existence of a Dyakonov-Tamm wave. If more than one solution exists, the corresponding Dyakonov-Tamm waves differ in phase speed and degree of localization to the interface. Fewer solutions were found when the two chiral STFs differ in many attributes.