Nonlinear optical processes can be dramatically enhanced via the use of localized surface plasmon modes in metal nanoparticles. Here we show how more elaborate structures, based on shape-controlled Au/Cu2O core/shell nanostructures, enable further enhancement of the nanoparticle third-harmonic scattering cross-section. The semiconducting component takes a twofold role in this structure, both providing a knob to tune the resonant frequency of the gold plasmon and providing resonant enhancement by virtue of its excitonic states. The advantages and deficiencies of using such core/shell metal/semiconductor structures are discussed.
Keywords: core/shell nanoparticles; plasmonics; third-harmonic generation.