High-efficiency second-harmonic generation in coupled nano Fabry–Perot thin resonators

In this paper we experimentally demonstrate second-harmonic generation (SHG) enhancement in thin 1D periodic plasmonic nanostructures on GaAs in the infrared spectral range. Due to the properly designed coupling of horizontal Fabry–Perot nanoresonators that occurs inside these structures, the obtained conversion efficiencies go up to the 10 −7 W −1 range. Moreover, we demonstrate that the engineering of the plasmonic nanoantenna dimensions on the same GaAs layer can lead to SHG enhancement for pump wavelengths ranging from 2.8 µm to 3.3 µm.