Unveiling the nature of cathodoluminescence from photon statistics

TL;DR

This paper explores the photon statistics of cathodoluminescence (CL), revealing how photon bunching encodes information about excitation processes, and distinguishes between coherent and incoherent CL.

Contribution

The study introduces a novel method to analyze photon statistics in CL, uncovering details of excitation processes and providing a universal framework for cascade reaction analysis.

Findings

Photon bunching reveals excitation process details.

Distinction between coherent and incoherent CL.

Universal formulation for cascade reactions.

Abstract

Cathodoluminescence (CL), the emission of light induced by accelerated free electrons, has been extensively utilized in various applications, such as displays, streak cameras, and high-spatial-resolution analysis of optical material, surpassing the diffraction limit of light. Despite its long history, the photon statistics of CL have only recently been examined, revealing unexpectedly large bunching of photons. Here we find that this peculiar photon bunching contains information of intervening excitation processes before the photon emission, which can be extracted from the photon statistics within each excitation event by a single free electron. Using this approach, we experimentally unveiled the statistical differences of coherent CL involving a single electromagnetic interaction process and incoherent CL involving multiple excitation processes. The developed formulation is universally applicable for particle generation processes in general to investigate the nature of cascade reactions.