A Tunable Transition Metal Dichalcogenide Entangled Photon-Pair Source

TL;DR

This paper presents a compact, tunable entangled photon-pair source using a 3R-stacked transition metal dichalcogenide crystal, suitable for space-limited quantum applications, with high efficiency and polarization control.

Contribution

It demonstrates a cubic micrometer scale entangled photon source with polarization entanglement and tunability, leveraging crystal symmetry without additional components.

Findings

Achieved polarization-entangled Bell states without extra components

Enabled simple control of entanglement tuning via pump polarization

Decoupled generation rate from state tuning for high efficiency

Abstract

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.