Identifying viable experimental configurations for the study of correlated electron-photon pairs in the transmission electron microscope

Abstract

Cathodoluminescence (CL) is the emission of light from a material, induced by the interaction with an incident electron. Setups for measuring cathodoluminescence inside a transmission electron microscope allow for simultaneous measurements of both emitted CL photons and the transmitted electrons that produced them on a single particle level. Due to energy and momentum conservation, it is clear that each emitted photon corresponds to an energy loss and a momentum transfer to the electron. Recent improvements in direct electron detectors, in particular those that use the ASIC Timepix3 are making it possible to study coherent CL on an event-by-event basis. This means that one can detect an individual electron and the individual photon it emits by verifying that they have been detected at the same time. One can consequently perform measurements on both particles. In this work the key requirements, which are needed to do experiments in the single electron-single photon regime are outlined. An experimental investigation of four different setups concerning their suitability to this kind of experiment is presented: the thin film, the multi-slit mask, the bulk under aloof excitation and the microsphere under aloof excitation. Finally, in-detail measurements regarding the thin film are laid out, as this approach seems to be the most promising for future experiments as part of the ongoing Quantum Optics with Electron-Photon Pairs (QOEPP) project.