Figure 2: Illustration of an optical antenna scattering.

(a) The structural dimensions of the plasmonic gold dimer studied are: D=230 nm, R=400 nm, T=60 nm, G=10 nm and H=60 nm. A SEM picture of the particle is shown in inset. (Scale bar, 200 nm.) Transmission is a sum of the forward scattered field and the incident beam. (b) Radiation pattern of a dipole on a glass–air interface. The substrate modifies the radiation pattern to resemble a Lambertian. Please note that the nanoantenna is illuminated from the glass side so that the high NA of the incident beam envelops most of the forward scattering distribution.