Visible-wavelength polarization-entangled photon source for quantum communication and imaging

We present a polarization-entangled photon pair source operating in the visible light range around 532 nm. Employing a collinear crossed-crystal scheme with type-I degenerate phase matching in barium borate (BBO), our source achieves a brightness of 9.5 k pairs/s/mW and a quantum state fidelity of 98.3%, making it a candidate for integration in microscopes and make use of the advantages of mid-visible optimized single-photon detection technologies. In order to study potential applications, we present a trade-off between source brightness and polarization entanglement visibility and propose use cases for different filtering configurations of the source, capable of a brightness up to 1.23 M pairs/s/mW. (C) 2022 Author(s).

Automated summary

In this study, a polarization-entangled photon pair source operating in the visible light range is presented, with high brightness and quantum state fidelity. By studying the trade-off between source brightness and entanglement visibility, application cases for different filtering configurations are proposed, achieving higher brightness.