  We demonstrate inverse design of plasmonic nanoantennas for directional light
scattering. Our method is based on a combination of full-field electrodynamical
simulations via the Green dyadic method and evolutionary optimization (EO).
Without any initial bias, we find that the geometries reproducibly found by EO,
work on the same principles as radio-frequency antennas. We demonstrate the
versatility of our approach by designing various directional optical antennas
for different scattering problems. EO based nanoantenna design has tremendous
potential for a multitude of applications like nano-scale information routing
and processing or single-molecule spectroscopy. Furthermore, EO can help to
derive general design rules and to identify inherent physical limitations for
photonic nanoparticles and metasurfaces.
