Fig. 1

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 wavelength