Effect of orientation on excitation of surface-plasmon-polariton waves guided by a columnar thin film deposited on a metal grating

Abstract

The excitation of surface-plasmon-polariton (SPP) waves guided by a columnar thin film (CTF) deposited on a one-dimensional metallic surface-relief grating was studied employing the rigorous coupled-wave approach, when the grating plane, the plane of incidence, and the morphologically significant plane of the CTF are all different. The incident plane wave in this grating-coupled configuration could be either por s-polarized. The absorptance was plotted against the polar angle of incidence at a fixed value of the free-space wavelength and absorptance peaks were correlated with the solution of the dispersion equation of the underlying canonical boundary-value problem for SPP waves. Both p-polarized and s-polarized plane waves can excite SPP waves, provided that either the plane of incidence and/or the morphologically significant plane of the CTF do not coincide with the grating plane. None, one, or multiple SPP-wave excitations are possible, depending on the orientations of the grating plane and the morphologically significant plane with respect to the plane of incidence. The direction of propagation of an SPP wave thus excited may not wholly lie in the plane of incidence.

Grating-coupled excitation of high-phase-speed Dyakonov surface waves

“…The second excitation occurs at θ 2 70.3 • , when k (0) xy = 0.9415k 0 differs by 4.8% from Re(q) = 0.9872k 0 . Although the double excitation of a surface wave had been noted earlier [26,36], this is the first report of the double excitation of a high-phase-speed surface wave.…”

“…An absorptance peak whose angular location is independent of L u beyond a threshold value when L g > 0 may indicate the excitation of a Dyakonov surface wave. In order to confirm, that angular location has to be compared to the angular locations predicted by the solutions of the canonical boundary-value problem; confirmation requires a reasonable match [17,26,30].…”

“…• , 360 • ) with respect to the x axis in the xy plane. The incident, reflected, and transmitted electric field phasors can be written as[2,26] …”

Morphological effects on the excitation of surface waves in the grating-coupled configuration

“…Therefore, we examined the absorptances of p-and s-polarized light for a CTF grown on a one-dimensional grating with all three planes distinct from each other. 38,39 The absorptances were computed as functions of the direction of incidence, and the excitation of surface waves was studied for various orientations of the three planes. The grating could be made of either a metal 38 or an isotropic dielectric material.…”

“…38,39 The absorptances were computed as functions of the direction of incidence, and the excitation of surface waves was studied for various orientations of the three planes. The grating could be made of either a metal 38 or an isotropic dielectric material. 39 The plan of this paper is as follows: The boundary-value problem for the grating-coupled configuration is briefly discussed in Sec.…”