Optimal interfacing a GHz-bandwidth heralded single photon source with on-demand, broadband quantum memories

Abstract

Photonics offers a route to fast and distributed quantum computing in ambient conditions, provided that photon sources and logic gates can be operated deterministically. Quantum memories, capable of storing and re-emitting photons on demand, enable quasi-deterministic operations by synchronising stochastic events. We recently interfaced a Raman-type quantum memory with a travelling-wave heralded photon source. Here we discuss the trade-space for the spectral characteristics of such sources, and we present measurements of our source, which represents a practical compromise enabling passive stability, high brightness in a single-pass configuration, high purity and good matching to our Cs vapour memory.