# Probing plasmon-NV$^0$ coupling at the nanometer scale with photons and fast electrons

## TL;DR

This study combines electron and photon spectroscopy to measure the Purcell effect at nanometer scales, revealing how surface plasmons influence NV0 center lifetimes in nanodiamonds with high spatial and temporal resolution.

## Contribution

It introduces a method integrating electron-based imaging and photon correlation spectroscopy to probe emitter-plasmon coupling at nanometer and nanosecond scales.

## Key findings

- Demonstrated lifetime reduction of NV0 centers in nanodiamond-nanocube dimers
- Quantified Purcell effect through statistical analysis of many emitters
- Achieved high-resolution measurement of emitter-plasmon interactions

## Abstract

The local density of optical states governs an emitters lifetime and quantum yield through the Purcell effect. It can be modified by a surface plasmon electromagnetic field, but such a field has a spatial extension limited to a few hundreds of nanometers, which complicates the use of optical methods to spatially probe the emitter-plasmon coupling. Here we show that a combination of electron-based imaging, spectroscopies and photon-based correlation spectroscopy enables measurement of the Purcell effect with nanometer and nanosecond spatio-temporal resolutions. Due to the large variability of radiative lifetimes of emitters embedded in nanoparticles with inhomogeneous sizes we relied on a statistical approach to unambiguously probe the coupling between nitrogen-vacancy centers (NV^0) in nanodiamonds and surface plasmons in silver nanocubes. We quantified the Purcell effect by measuring the NV^0 excited state lifetimes in a large number of either isolated nanodiamonds or nanodiamond-nanocube dimers and demonstrated a statistically significant lifetime reduction for dimers.