Entangled photon-pair sources are at the core of quantum applications like quantum key distribution, sensing, and imaging. Operation in space-limited and adverse environments such as in satellite-based and mobile communication requires robust entanglement sources with minimal size and weight requirements. Here, we meet this challenge by realizing a cubic micrometer scale entangled photon-pair source in a 3R-stacked transition metal dichalcogenide crystal. Its crystal symmetry enables the generation of polarization-entangled Bell states without additional components and provides tunability by simple control of the pump polarization. Remarkably, generation rate and state tuning are decoupled, leading to equal generation efficiency and no loss of entanglement. Combining transition metal dichalcogenides with monolithic cavities and integrated photonic circuitry or using quasi-phasematching opens the gate towards ultrasmall and scalable quantum devices.
@article{arxiv.2311.16036,
title = {A Tunable Transition Metal Dichalcogenide Entangled Photon-Pair Source},
author = {Maximilian A. Weissflog and Anna Fedotova and Yilin Tang and Elkin A. Santos and Benjamin Laudert and Saniya Shinde and Fatemeh Abtahi and Mina Afsharnia and Inmaculada Pérez Pérez and Sebastian Ritter and Hao Qin and Jiri Janousek and Sai Shradha and Isabelle Staude and Sina Saravi and Thomas Pertsch and Frank Setzpfandt and Yuerui Lu and Falk Eilenberger},
journal= {arXiv preprint arXiv:2311.16036},
year = {2023}
}