Figure 3: Reflectivity of 2D groove arrays in gold.
From: Plasmonic black gold by adiabatic nanofocusing and absorption of light in ultra-sharp convex grooves
(a) Scanning electron microscopy image (under angled view) of a 250-nm-period array of orthogonally crossed ultra-sharp convex 250-nm-deep grooves milled in gold (scale bar, 700 nm). (b,c) Optical microscope images of the 250-nm-period groove array obtained for two orthogonal polarizations of incident light (scale bar, 7 μm) that are indicated with respect to the axes marked in (a). (d) Reflectivity spectra of x- (solid lines) and y-polarized (dashed lines) light (as marked in a) for crossed convex grooves of different depths H arranged in 2D arrays with different periods Λ are shown with green (H=400 nm, Λ=350 nm) and red (H=250 nm, Λ=250 nm) lines.
