Heralded pure single photons

Xue-lin Liu, Tong Xiang, Xianfeng Chen

Xavier Barcons Planas, Helen M. Chrzanowski, Leon Meßner +1 more

Highly efficient sources of pure single photons are essential for photonic quantum technologies. We present a source of pure single-photons with 85% heralding efficiency based on pulsed spontaneous parametric down-conversion in a monolithic cavity.

Matthew D. Eisaman

Jefferson Flórez, Omar Calderón-Losada, Alejandra Valencia +1 more

We present a detailed study on the properties of single photons generated by spontaneous parametric down conversion (SPDC) when both the spectral and spatial degrees of freedom are controlled by means of filters. Our results show that it is possible to obtain pure heralded single photons with high heralding efficiency despite the use of filters. Moreover, we report an asymmetry on the single-photon properties exhibited in type-II SPDC sources that depends on choosing the signal or the idler photon as the heralding one.

Daniel Fernando Borrero Landazabal, Kaisa Laiho

Lijian Zhang, Christoph Söller, Offir Cohen +2 more

Sources of single photons in pure quantum states are essential to many quantum optics applications. We explore a technique, known as group-velocity matching, that enables the heralded generation of pure single photons through nonlinear optical processes. It reduces or eliminates the requirement of spectral filtering that conventional sources rely on to achieve high purity, therefore increasing both heralding efficiency and photon flux. Implementation in both spontaneous parametric downconversion and spontaneous four-wave mixing is studied as we discuss several recent experimental realizations demonstrating purity of more than 0.84 for the heralded photons.