Photon bunching in cathodoluminescence induced by indirect electron excitation

TL;DR

This paper investigates photon bunching phenomena in cathodoluminescence caused by indirect electron excitation, revealing significant changes in photon correlations that impact nanoscale optical material characterization.

Contribution

It demonstrates how indirect electron interactions significantly alter photon bunching in cathodoluminescence, advancing understanding of nanoscale optical property measurement.

Findings

Photon bunching can reach $g^{2}(0)$ values near $10^4$ due to indirect electron excitation.

Changes in photon bunching affect interpretation of cathodoluminescence correlation functions.

Results enable improved nanoscale optical characterization of beam-sensitive materials.

Abstract

The impulsive excitation of ensembles of excitons or color centers by a high-energy electron beam results in the observation of photon bunching in the second-order correlation function of the cathodoluminescence generated by those emitters. Photon bunching in cathodoluminescence microscopy can be used to resolve the excited-state dynamics and the excitation and emission efficiency of nanoscale materials, and it can be used to probe interactions between emitters and nanophotonic cavities. Here, we report substantial changes in the measured bunching induced by indirect electron interactions (with indirect electron excitation inducing $g^{2}(0)$ values approaching $10^4$). This result is critical to the interpretation of $g^{2}(\tau)$ in cathodoluminescence microscopies, and, more importantly, it provides a foundation for the nanoscale characterization of optical properties in beam-sensitive materials.