Towards Ghost Imaging with Electron-Photon-Pairs

Abstract

Since the introduction of time-resolved direct electron detectors to transmission electron microscopy (TEM), there has been a growing interest in studying the correlations between an electron and the cathodoluminescence (CL) photons it produces [1,2,3]. In this contribution, we demonstrate “ghost imaging” [4], a method adapted from photonic quantum optics that leverages position or momentum correlations within electron-photon pairs for imaging. In a TEM, working at 200 keV, we generate electron-photon pairs via the process of transition radiation using a thin silicon membrane (see Fig. 1). We collect the photons using a custom-made parabolic mirror and let the photons interact with an arbitrary absorptive mask placed in the image plane of the collection system (see grating mask in Fig. 1b), thus imprinting the shape of this mask in the measured photon distribution. Using a single photon counting module and time tagger, we can match each detected photon to its emitting electron and retrieve the mask shape in the distribution of the corresponding electrons (Fig. 1e). This is remarkable, as the electron did not interact with the object; the information about the mask shape is mediated purely through the correlations between the two particles. In a recent publication [5], we employed ghost imaging in order to demonstrate electron-photon entanglement. We will present ghost imaging with considerably better spatial resolution and explain how this might allow us to show the Einstein-Podolsky-Rosen paradox using electron-photon pairs.