Dresden 2011 – wissenschaftliches Programm
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SKM-SYNP: SKM-Symposium Semiconductor Nanophotonics: Quantum Optics and Devices
SKM-SYNP 1: Semiconductor Nanophotonics: Quantum Optics and Devices
SKM-SYNP 1.5: Hauptvortrag
Mittwoch, 16. März 2011, 16:45–17:15, TRE Ma
Semiconductor Devices for Quantum Photonics — •Andrew Shields1, Anthony Bennett1, Mark Stevenson1, Cameron Salter1,2, Raj Patel1,2, Ian Farrer2, Christine Nicoll2, and David Ritchie2 — 1Toshiba Research Europe Ltd, 208, Cambridge Science Park, Milton Rd, Cambridge CB40GZ. UK — 2Cavendish Laboratory, University of Cambridge, Madingley Road, Cambridge CB30HE. UK
Often referred to as "artificial atoms", quantum dots possess discrete energy levels that make them viable hosts for electronic qubits or sources of photonic qubits. However, unlike atoms, no two quantum dots are alike, a complication for quantum information schemes requiring either indistinguishable electronic states in different quantum dots, or indistinguishable photons emitted from different quantum dots. We demonstrate here that the transition energy of a quantum dot can be continuously varied, over a range much larger than the linewidth, using an electric field applied in a diode structure. By tuning individual quantum dots to identical energies we demonstrate two-photon interference of photons emitted from truly remote, independent quantum dots, thereby overcoming a significant barrier to scalable quantum information processing. Quantum dots may be used not only to generate single photons, but also polarization entangled pairs. We demonstrate here an electrically-driven entangled light source, based upon the electroluminescence of a single quantum dot in a semiconductor light emitting diode (LED). The device can be operated with continuous or pulsed current injection, with an entanglement fidelity in the latter case of up to 0.83+/-0.03. We also observe a violation of Bell's inequality with the device emission.