Colossal photon bunching in quasiparticle-mediated nanodiamond cathodoluminescence

TL;DR

This study demonstrates extremely high photon bunching in nanodiamond NV centers excited by electron beams, revealing plasmon-mediated enhancement and phonon sideband effects crucial for quantum nanophotonics.

Contribution

It reports the first observation of colossal photon bunching ($g^{(2)}(0)>45$) in nanodiamond cathodoluminescence, highlighting plasmonic control and phonon sideband influence.

Findings

Photon bunching exceeds 45 in nanodiamond NV centers.

Plasmon coupling increases luminescence intensity 16-fold.

Photon bunching is mediated by NV$^0$ phonon sidebands.

Abstract

Nanoscale control over the second-order photon correlation function $g^{(2)}(\tau)$ is critical to emerging research in nonlinear nanophotonics and integrated quantum information science. Here we report on quasiparticle control of photon bunching with $g^{(2)}(0)>45$ in the cathodoluminescence of nanodiamond nitrogen vacancy (NV$^0$) centers excited by a converged electron beam in an aberration-corrected scanning transmission electron microscope. Plasmon-mediated NV$^0$ cathodoluminescence exhibits a 16-fold increase in luminescence intensity correlated with a three fold reduction in photon bunching compared with that of uncoupled NV$^0$ centers. This effect is ascribed to the excitation of single temporally uncorrelated NV$^0$ centers by single surface plasmon polaritons. Spectrally resolved Hanbury Brown--Twiss interferometry is employed to demonstrate that the bunching is mediated by the NV$^0$ phonon sidebands, while no observable bunching is detected at the zero-phonon line. The data are consistent with fast phonon-mediated recombination dynamics, a conclusion substantiated by agreement between Bayesian regression and Monte Carlo models of superthermal NV$^0$ luminescence.