Enhancement of second-harmonic generation from gold nanoparticles through passive elements

Antennas are devices that enable the coupling of electromagnetic radiation from a source into the far field or vice versa [1]. Recent advances in nanofabrication have allowed antenna concepts to be moved from the radio-frequency to the optical domain [2]. Passive elements play an important role in the design of antennas, usually used to improve the directionality of radiation from the antennas. In this Paper, we show that the presence of passive elements enhances the efficiency of second-harmonic generation (SHG).