Optimization of second-harmonic generation from touching plasmonic wires

We employ transformation optics to optimize the generic nonlinear wave interaction of second-harmonic generation (SHG) from a pair of touching metallic wires. We demonstrate a six orders of magnitude increase in efficiency with respect to SHG from a single wire, and a ten orders of magnitude increase in the second-harmonic scattered power by increasing the background permittivity. These results have clear implications for the design of nanostructured metallic frequency-conversion devices. Finally, we exploit our analytic solution of a nontrivial nanophotonic geometry as a platform for performing a critical comparison of the strengths, weaknesses, and validity of other prevailing theoretical approaches previously employed for nonlinear wave interactions at the nanoscale.

Automated summary

Utilizing transformation optics, we significantly improved the efficiency of second-harmonic generation from metallic wires and increased the second-harmonic scattered power drastically by adjusting the background permittivity. These findings are crucial for the design of nanostructured metallic frequency-conversion devices. Additionally, we compared the strengths, weaknesses, and validity of different theoretical approaches for nonlinear wave interactions at the nanoscale using our analytic solution of a complex nanophotonic geometry.