Full text loading...
(a) Interface between a homogeneous medium (permittivity ) and a periodic half-space composed of an array of semi-infinite slits perforated in the metal (permittivity ). The are the plane-wave scattering coefficients used in the analytical model, and and represent the normalized SPP-excitation rates. (b) (red) and (blue) values calculated with the fully-vectorial RCWA formalism for gold , , , and . The black circles show the SPP damping, , on flat metal surfaces.
(a) Total SPP-excitation rates in the diagram at visible and infrared frequencies. The results hold for the geometry of Fig. 1 ( and ) and are obtained with the RCWA formalism. The solid-red and dashed-white curves, respectively, represent the Rayleigh anomalies and the folded dispersion relation of SPPs on flat gold surfaces. (b) Enlarged views in the vicinity of the point, and [shown in the dashed box in (a)]. The points A and B represent the SPP and Rayleigh wavelength at normal incidence. (c) The same as in (b) but calculated with the analytical model. (d) (red) and (blue) values obtained with the analytical model of Eq. (2) for various grating periods, and for and . The dashed-green lines locate the Rayleigh wavelengths.
Microscopic interpretation for the influence of the metal permittivity on the normalized SPP-excitation rate for . The two lower curves represents fundamental scattering coefficients, and , for isolated slits whose widths are equal to those used for the grating calculation, . Both and scales as , shown with the solid-green curve. The pure SPP model and the analytical model predictions are shown, respectively, with dashed-blue and solid-red curves. The black circles show fully-vectorial RCWA data.
Article metrics loading...