Figure 5

Experiment demonstration of continuously tunable contrast between SPP excitation along +x and –x directions by varying the ellipticity of the input light at λ=1020 nm. Points A–G correspond to the CCD images for η=−1 (θ=−45°), η=−0.364 (θ=−20°), η=−0.176 (θ=−10°), η=0 (θ=0°), η=0.176 (θ=10°), η=0.364 (θ=20°) and η=1 (θ=45°). The symbols show the y-integrated output power at the two positions for outcoupler vs. ellipticity ranging from [−1, 1]. The solid curves are calculated by using full wave simulation by COMSOL Multiphysics to investigate the peak intensities at the metal and dielectric boundaries at each side. All intensities are normalized in the range of [0, 1]. CCD, charge coupled device; SPP, surface plasmon polariton.