Figure 1: Reflection of light by 1D groove arrays.
From: Plasmonic black gold by adiabatic nanofocusing and absorption of light in ultra-sharp convex grooves
(a) Schematic of the considered configuration, showing orientation of a groove array and incident plane wave, whose phase fronts are represented by grey squares on the arrow indicating the propagation direction of incident light. (b) Geometrical parameters defining the profile of groove arrays. (c) Reflectivity spectra calculated for 250-nm-period arrays of 500-nm-deep grooves with the following parameters kept constant: a=r=10 nm. Solid lines correspond to the reflection spectra of p-polarized light (which in our case is polarized along the y axis) calculated for normal incidence (θ=0°) and a minimum gap width δ=0.3 nm (which is close to the gold atom diameter), and for different inclination angles: α=0, 1.3, 2.6, 6.5 and 12.5°. Reflectivity spectrum for a flat gold surface is shown with a dashed line. Reflectivity spectra for s-polarized (which, in our case, is polarized along the x axis at normal incidence) light are shown with dash-dotted lines for two limiting inclination angles: α=0 and 12.5°. Gold dielectric constants are taken from Johnson and Christy29.
