Measurement of the Second-Order Polarizability of Silver Nanoparticles With Reference-Free Hyper-Rayleigh Scattering for Entangled Photon Pair Interaction

Two-photon interactions of entangled-photon pairs with metallic nanoparticles (NPs) can be enhanced by localized surface-plasmon resonance. Recently, we have described how the properties this quantum light-matter interaction deduced from classical second-harmonic generation measurements performed using a reference-free hyper-Rayleigh scattering method. Herein, report results such classical-light characterization measurements. We obtain large hyperpolarizability for NPs, present dependence on NPs' spectral features, and show dipolar emission pattern signal. Our used to optimize pair NPs enable first ever detection process. Moreover, these suggest that may as source ultra-broadband through nonphase-matched spontaneous parametric down-conversion.