Steering second-harmonic radiation through local excitations of plasmon

We propose an approach of steering the second harmonic (SH) emission from a single plasmonic structure, through local excitations of plasmon. The proposed idea is confirmed experimentally, by adjusting the incident beam position at the fundamental frequency, on a single plasmonic antenna. A significant directivity change (+/- 52 degrees) for the SH emission is observed with submicrometer adjustment (+/- 250 nm) of the excitation beam position, over broadband SH frequencies. Providing a simple method of controlling the directivity of frequency-converted light, our approach paves the way to new design strategy for nonlinear optical devices with various nonlinear wavefronts. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement