Delocalization of nonlinear optical responses in plasmonic nanoantennas

TL;DR

This paper demonstrates that nonlinear optical responses in plasmonic nanoantennas can be remotely excited and emitted from the entire antenna via propagating surface plasmons, enabling tailored nonlinear optical functionalities.

Contribution

It reveals that nonlinear responses are transported by surface plasmons, allowing remote control and design of nonlinear optical processes in plasmonic nanoantennas.

Findings

Nonlinear radiations can be emitted from the entire antenna

Far-field patterns reveal the nature of nonlinear processes

Surface plasmon propagation mediates nonlinear responses

Abstract

Remote excitation and emission of two-photon luminescence and second-harmonic generation are observed in micrometer long gold rod optical antennas upon local illumination with a tightly focused near-infrared femtosecond laser beam. We show that the nonlinear radiations can be emitted from the entire antenna and the measured far-field angular patterns bear the information regarding the nature and origins of the respective nonlinear processes. We demonstrate that the nonlinear responses are transported by the propagating surface plasmon at excitation frequency, enabling thereby polariton-mediated tailoring and design of nonlinear responses.