Reducing multi-photon rates in pulsed down-conversion by temporal multiplexing

TL;DR

This paper introduces a method to decrease multi-photon emission rates in pulsed down-conversion by increasing laser repetition rate and reducing pulse energy, enhancing quantum gate performance.

Contribution

The authors demonstrate a simple, effective technique using extra-cavity control to improve quantum photonic experiments by reducing unwanted multi-photon events.

Findings

Improved non-classical interference visibility in 2- and 4-photon experiments

Enhanced quantum-gate fidelity in 2-photon operations

Increased entangled state production efficiency

Abstract

We present a simple technique to reduce the emission rate of higher-order photon events from pulsed spontaneous parametric down-conversion. The technique uses extra-cavity control over a mode locked ultrafast laser to simultaneously increase repetition rate and reduce the energy of each pulse from the pump beam. We apply our scheme to a photonic quantum gate, showing improvements in the non-classical interference visibility for 2-photon and 4-photon experiments, and in the quantum-gate fidelity and entangled state production in the 2-photon case.