Driving plasmonic nanoantennas with triangular lasers and slot waveguides

Plasmonic nanoantennas can generate high-intensity electric fields in a very small area. However, being passive devices, they need to be excited by external laser sources. The excitation of nanoantennas by semiconductor lasers can be inefficient and a significant amount of light may return back to the laser source after being scattered by the nanoantenna. In this paper, it is shown that the amount of light being returned to the semiconductor laser can be reduced by using dielectric slot waveguides. These waveguides can transport the incident light to the nanoantennas, but the amount of nondirectional back-scattered light is reduced after propagation through the slot waveguide.