Tunable entanglement distillation of spatially correlated down-converted photons

TL;DR

This paper introduces a tunable, real-time entanglement distillation method for spatially correlated photons from SPDC, using non-Gaussian filters and a single-photon camera to enhance entanglement by about 67%.

Contribution

It presents a novel, tunable technique for entanglement distillation with real-time certification using a programmable spatial light modulator and EMCCD camera.

Findings

Achieved approximately 67% net gain in entanglement.

Implemented real-time certification of entanglement.

Demonstrated fine control over the Schmidt number.

Abstract

We report on a new technique for entanglement distillation of the bipartite continuous variable state of spatially correlated photons generated in the spontaneous parametric down-conversion process (SPDC), where tunable non-Gaussian operations are implemented and the post-processed entanglement is certified in real-time using a single-photon sensitive electron multiplying CCD (EMCCD) camera. The local operations are performed using non-Gaussian filters modulated into a programmable spatial light modulator and, by using the EMCCD camera for actively recording the probability distributions of the twin-photons, one has fine control of the Schmidt number of the distilled state. We show that even simple non-Gaussian filters can be finely tuned to a ~67% net gain of the initial entanglement generated in the SPDC process.