München 2004 – scientific programme
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Q: Quantenoptik und Photonik
Q 45: Quanteninformation IV
Q 45.2: Talk
Friday, March 26, 2004, 11:30–11:45, HS 101
Quantum dot single photon sources: prospects for applications in linear optics quantum computation — •Alper Kiraz1, Mete Atatüre2, and Atac Imamoḡlu2 — 1Department Chemie, Ludwig-Maximilians Universität München, Butenandtstr. 11, D-81377 München, Germany — 2Quantenelektronik, ETH-Hönggerberg, HPT G12, CH-8093 Zurich, Switzerland
An optical source that produces single photon pulses on demand has potential applications in linear optics quantum computation, provided that stringent requirements on indistinguishability and collection efficiency of the generated photons are met[1]. We show that these are conflicting requirements for the recently demonstrated quantum dot single photon sources that are incoherently pumped via reservoirs[2].
As a model for a coherently pumped single photon source, we consider cavity-assisted Raman transitions in a single three-level system in the Λ-configuration[3].We demonstrate that using such a source, arbitrarily high collection efficiency and indistinguishability of the generated photons can be obtained simultaneously with increased cavity coupling. In the absence of dephasing, our calculations reveal maximum collection efficiency and indistinguishability of 99 % for a Purcell factor of 40, without necessitating the strong coupling limit. This regime, that is readily available in current cavity-QED experiments using atoms, can potentially be reached with a single quantum dot embedded in a microcavity.
[1] E. Knill et al., Nature 409, 46 (2001).
[2] P. Michler et al., Science 290, 2282 (2000).
[3] A. Kuhn et al., Phys. Rev. Lett. 89, 067901 (2002).