Discrimination of coherent and incoherent cathodoluminescence using temporal photon correlations

TL;DR

This paper introduces a time-resolved coincidence detection method to distinguish between coherent and incoherent cathodoluminescence, aiding material analysis and understanding of electron-matter interactions.

Contribution

The study demonstrates a novel approach using photon correlations to separate and quantify coherent and incoherent CL contributions in a proof-of-concept experiment.

Findings

Coincidence counts reveal photon bunching at small time delays.

Bunching peak attributed to coherent CL (Cherenkov radiation).

Method enables discrimination and quantification of CL components.

Abstract

We present a method to separate coherent and incoherent contributions of cathodoluminescence (CL) by using a time-resolved coincidence detection scheme. For a proof-of-concept experiment, we generate CL by irradiating an optical multimode fiber with relativistic electrons in a transmission electron microscope. A temporal analysis of the CL reveals a large peak in coincidence counts for small time delays, also known as photon bunching. Additional measurements allow us to attribute the bunching peak to the temporal correlations of coherent CL (Cherenkov radiation) created by individual electrons. Thereby, we show that coincidence measurements can be employed to discriminate coherent from incoherent CL and to quantify their contribution to the detected CL signal. This method provides additional information for the correct interpretation of CL, which is essential for material characterization. Furthermore, it might facilitate the study of coherent electron-matter interaction.