Despite their many applications over the last decades, entangled and single-photon sources from probabilistic sources such as spontaneous parametric downconversion have limited performance due to the presence of unwanted multi-pair events. For example, it is not possible to produce a heralded single photon with a probability exceeding 25%. However, by incorporating low-loss multiplexing (in our case, time-bin multiplexing), one can greatly enhance device performance. We will review our recent work in this area, and speculate about the future.
Paul G. Kwiat is the Bardeen Chair in Physics, at the University of Illinois, in Urbana-Champaign, and is the inaugural Director of the Illinois Quantum Information Science and Technology Center (IQUIST). A Fellow of the American Physical Society and the Optical Society of America, he has given invited talks at numerous national and international conferences, and has authored over 160 articles on various topics in quantum optics and quantum information, including several review articles. His research focuses on optical implementations of quantum information protocols, particularly using entangled—and hyperentangled—photons from parametric down-conversion. He received the Optical Society of America 2009 R. W. Wood Prize, as the primary inventor of the world’s first sources of polarization-entangled photons from down-conversion, which have been used for quantum cryptography, dense-coding, quantum teleportation, quantum metrology, and realizing optical quantum gates. He has also done pioneering work on high-efficiency single-photon detectors, frequency-upconversion-based detection, and high-speed quantum random number generation.