Towards ghost imaging by correlation measurements of electron-photon pairs

Abstract

In recent years, fast electron microscopy has garnered increased interest within the scientific community. Particularly, temporal correlation measurements have proven to dramatically enhance the useful signal by suppressing background noise. Here, we introduce a new method of imaging at the intersection of quantum optics and electron microscopy. Ghost imaging, also known as coincidence imaging, of an object is a method in classical and quantum physics that involves constructing an image by gathering information from past correlation measurements. We perform coincidence measurements using electron-photon pairs which are correlated in momentum and position. To produce correlated electron-photon pairs we use a transmission electron microscope (TEM) working at an acceleration voltage of 200 keV to illuminate a thin monocrystalline silicon membrane of 100 nm thickness. Primary electrons scatter inelastically inside the membrane and undergo a small momentum deflection, simultaneously emitting coherent photon emission through a process known as cathodoluminescence (CL). As a result, the emitted photons are correlated in momentum and position with the transmitted electrons. We guide correlated photons through an object, which we are interested in imaging, and detect electrons directly with a pixelated camera. Despite electrons never directly interacting with the object, we are able to perform ghost imaging of the object through correlated electron-photon pairs.