Spectrally Resolved Second-Order Coherence of Nanoscale Plasmonic-NV Center Hybrids*

We report colossal photon bunching of g⁽²⁾(0) ≈ 49 in the cathodoluminescence (CL) of neutral nitrogen vacancy (NV⁰) centers in nanodiamonds excited by an electron beam in a scanning transmission electron microscope. Spectrally filtered Hanbury Brown-Twiss (HBT) interferometry suggests that the bunching source is the phonon sideband, whereas no bunching is observed at the zero-phonon line. Our results are statistically consistent with fast phonon-mediated recombination dynamics, supported by validation between a Bayesian regression and a Monte-Carlo model of NV⁰ luminescence. We expand upon this work by leveraging well-developed nanofabrication techniques to fabricate hybrid quantum systems of NV centers coupled to surface plasmon polaritons (SPPs). The semi-classical dynamics of these systems will be estimated by finite difference time domain simulations to inform a Jaynes-Cummings model. The photon statistics of a multi-quantum emitter system coupled to SPPs will be characterized via HBT interferometry of the CL and photoluminescence of said systems.