Enhanced photon-pair generation from a van der Waals metasurface

Photon pairs generated by spontaneous parametric down-conversion (SPDC) are playing a pivotal role in many quantum applications such as quantum computing, quantum imaging and quantum communication. Metasurfaces, which are two-dimensional arrays of nanostructures, have been studied intensively to enhance SPDC and provide additional functionalities over the bulky optical systems [1]. Van der Waals (vdWs) layered materials have emerged as promising platform for quantum light sources, owing to their unique properties [2,3]. For example, vdWs materials offer high refractive index, a high nonlinear susceptibility, and compatibility with on-chip integration.