Figure 4
From: Strong optical absorption of a metallic film to induce a lensing effect in the visible region
A schematic of the experimental setup used to measure the intensity profiles of a laser beam transmitted through prism-like Au film samples at different x positions. The near-field image of the beam spot (λ = 632.8 nm) that emerged from the sample was displayed on a screen located at a distance of 200 mm from the sample in the z direction. A precision displacement stage was used to move the laser transmission position on the sample (with or without a Au film) in the x direction. The beam spots imaged on the screen were recorded using a CCD camera with 1317 × 1035 pixels, a pixel size of 6.8 × 6.8 μm2 and a 12-bit A/D converter resolution. Two typical images are shown, (a) for the sample consisting of a glass substrate without a Au film and (b) for the Au film sample with a prism angle of 62.0 μrad.
