Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 11: Quantum information systems: mostly quantum dots

HL 11.1: Vortrag

Montag, 11. März 2013, 12:00–12:15, H16

Phase-locked indistinguishable photons from a solid-state source — •Clemens Matthiesen, Martin Geller, Carsten H. H. Schulte, Claire Le Gall, Jack Hansom, Zhenyong Li, and Mete Atature — Cavendish Laboratory, University of Cambridge, Cambridge, United Kingdom

Recent years have seen significant progress in the control of solid-state quantum bits, such as spins in self-assembled InAs quantum dots (QDs). Entangling individual spins through quantum interference of flying qubits has been identified as a promising approach to realising a quantum network of distant spins. Hoever, generating indistinguishable photons (as flying qubits) from separate QDs has proved challenging, due to fast and slow dephasing of the optical QD transitions.

Resonance fluorescence in the Heitler regime [1] provides access to single photons with coherence well beyond the Fourier transform limit of the transition, and holds the promise to circumvent environment-induced dephasing. We first demonstrate that the coherently generated single photons from a single QD display mutual coherence with the excitation laser on a timescale exceeding 3 seconds. Exploiting this degree of mutual coherence we shape single photons pulses. Separate photons generated phase-locked to the excitation laser field are shown to be fundamentally indistinguishable [2], lending themselves to creation of distant entanglement through quantum interference.

[1]Matthiesen et al. Phys. Rev. Lett. 108, 093602 (2012). [2]Matthiesen et al. arXiv:1208.1689 [quant-ph] (2012).