Quantum memories and large-scale quantum coherence based on Raman interactions
Institute of Electrical and Electronics Engineers (IEEE) (2013) 173-174
On-chip low loss heralded source of pure single photons
Optics Express 21:11 (2013) 13522-13532
Abstract:
A key obstacle to the experimental realization of many photonic quantum-enhanced technologies is the lack of low-loss sources of single photons in pure quantum states. We demonstrate a promising solution: generation of heralded single photons in a silica photonic chip by spontaneous four-wave mixing. A heralding efficiency of 40%, corresponding to a preparation efficiency of 80% accounting for detector performance, is achieved due to efficient coupling of the low-loss source to optical fibers. A single photon purity of 0:86 is measured from the source number statistics without narrow spectral filtering, and confirmed by direct measurement of the joint spectral intensity. We calculate that similar high-heralded-purity output can be obtained from visible to telecom spectral regions using this approach. On-chip silica sources can have immediate application in a wide range of single-photon quantum optics applications which employ silica photonics. © 2013 Optical Society of America.Towards scalable photonics via quantum storage
Proceedings of SPIE - The International Society for Optical Engineering 8636 (2013)
Abstract:
Single photons are a vital resource for optical quantum information processing. efficient and deterministic single photon sources do not yet exist, however. To date, experimental demonstrations of quantum processing primitives have been implemented using non-deterministic sources combined with heralding and/or postselection. Unfortunately, even for eight photons, the data rates are already so low as to make most experiments impracticable. It is well known that quantum memories, capable of storing photons until they are needed, are a potential solution to this 'scaling catastrophe'. Here, we analyze two protocols for generating multiphoton states using quantum memories, showing how the production rates can be enhanced by many orders of magnitude. We identify the time-bandwidth product as a key figure of merit in this connection. © 2013 SPIE.Sequential path entanglement for quantum metrology
Scientific Reports 3 (2013)
Abstract:
Path entanglement is a key resource for quantum metrology. Using path-entangled states, the standard quantum limit can be beaten, and the Heisenberg limit can be achieved. However, the preparation and detection of such states scales unfavourably with the number of photons. Here we introduce sequential path entanglement, in which photons are distributed across distinct time bins with arbitrary separation, as a resource for quantum metrology. We demonstrate a scheme for converting polarization Greenberger-Horne-Zeilinger entanglement into sequential path entanglement. We observe the same enhanced phase resolution expected for conventional path entanglement, independent of the delay between consecutive photons. Sequential path entanglement can be prepared comparably easily from polarization entanglement, can be detected without using photon-number-resolving detectors, and enables novel applications.Direct observation of sub-binomial light
Institute of Electrical and Electronics Engineers (IEEE) (2013) 1-1