Second-Harmonic Generation Enhancement by Film-Coupled Plasmonic Nanopatch Antennas With Integrated Quantum Emitters

TL;DR

This paper demonstrates a significant enhancement in second harmonic generation using film-coupled plasmonic nanopatch antennas with integrated quantum emitters, enabling advanced control of light-matter interactions for optical applications.

Contribution

It introduces a novel nanopatch antenna design with integrated quantum emitters that achieves high second harmonic generation enhancement and strong coupling effects.

Findings

10^4-fold increase in second harmonic intensity

Observation of nonlinear exciton-polariton strong coupling

Potential for nonlinear optical control in quantum regimes

Abstract

Plasmonic nanocavities have proven to be a powerful optical platform for confining light at a length scale much smaller than the diffraction limit. Enhanced electromagnetic fields within the cavity mode volume enable multiple significant effects that lead to applications in both the linear and nonlinear optical regimes. In this work, we demonstrate enhanced second harmonic generation from individual plasmonic nanopatch antennas which are formed by separating silver nanocubes from a smooth gold film using a sub-10 nm zinc oxide spacer layer. When the nanopatch antennas are excited at their fundamental plasmon frequency, a 10^4-fold increase in the intensity of the second harmonic generation wave is observed. Moreover, by integrating quantum emitters that have an absorption energy at the fundamental frequency, a second order nonlinear exciton-polariton strong coupling response is observed with a Rabi splitting energy of 19 meV. The nonlinear frequency conversion using nanopatch antennas thus provides an excellent platform for nonlinear control of the light-matter interactions in both weak and strong coupling regimes which will have a great potential for applications in optical engineering and information processing.