A slanted-nanoaperture metal lens: subdiffraction-limited focusing of light in the intermediate field region

Dipole radiation patterns. a A tilted dipole placed on metal surface. The tilt angle α refers to the substrate normal. b Horizontal dipole (α？=？90°). c Vertical dipole (α？=？0°). d Titled dipole (α？=？15°). Three different metals are assumed for substrate: Ag (red), Al (green) and Cr (blue). The radiation patterns calculated at 633 nm wavelengt