Time-multiplexed heralded single-photon source

Photons have proven to be excellent carriers of quantum information and play essential roles in numerous quantum information processing (QIP) applications. In particular, heralded single-photon sources via spontaneous parametric-down conversion (SPDC) have been a key technology for demonstrating small-scale QIP, yet their low generation efficiency is a critical limitation to furthering the scale-up of optical QIP technology. In order to efficiently overcome the probabilistic nature of SPDC, here we demonstrate time multiplexing for up to 30 time slots of a periodically pumped heralded single-photon source using a switchable low-loss optical storage cavity. We observe a maximum single-photon probability of 38.6±0.4% in periodic output time windows, corresponding to ∼6 times enhancement over a nonmultiplexed source but with no increase in the contribution of unwanted multiphoton events. Combining this time-multiplexing technique with a heralded source producing pure single-photon states should enable larger-scale optical QIP systems than previously realized.