Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 47: Quantum Information: Quantum Computer
Q 47.4: Vortrag
Donnerstag, 17. März 2011, 11:15–11:30, BAR Schön
Coherent Photon Conversion enabling Nonlinear Optical Quantum Computing — Nathan K. Langford1,2, •Sven Ramelow1,2, Robert Prevedel1,2, William J. Munro3, Gerard J. Milburn4, and Anton Zeilinger1,2 — 1University of Vienna, Austria — 2IQOQI Vienna, ÖAW, Austria — 3NTT Laboratories, Japan — 4University of Queensland, Australia
Photonic systems offer many advantages for quantum information technologies such as minimal decoherence and almost trivial single qubit operations. The key unresolved challenges for a working optical quantum computer are scaleable on-demand single photon sources; deterministic two-photon interactions; and near 100%-efficient detection. Here, we introduce a novel four-wave mixing process called coherent photon conversion (CPC). This process potential provides a very wide range of tools for optical quantum information processing and promises to enable scalable sources, efficient detection and deterministic entangling gates. The CPC process is a pumped χ(3) interaction inducing an effective χ(2) nonlinearity which is enhanced by the pump power. With a single-photon input and high enough effective nonlinearity deterministic photon doubling can be achieved - one key element in our scheme. We present first experiments with photonic crystal fibers that demonstrate the four-colour nonlinear process underlying CPC. We observe correlated photon-pair production at the predicted wavelengths, experimentally characterise the enhancement of the interaction strength by varying the pump power and discuss how to reach the near-deterministic regime with current technology.