Issue
EPL
Volume 86, Number 1, April 2009
Article Number 14007
Number of page(s) 5
Section Electromagnetism, Optics, Acoustics, Heat Transfer, Classical Mechanics, and Fluid Dynamics
DOI http://dx.doi.org/10.1209/0295-5075/86/14007
Published online 22 April 2009
EPL, 86 (2009) 14007
DOI: 10.1209/0295-5075/86/14007

Perfect excitation of a matter qubit by a single photon in free space

M. Stobińska1, 2, G. Alber3 and G. Leuchs1, 2

1   Max Planck Institute for the Science of Light - Günter-Scharowsky-Str. 1, Bau 24, 91058 Erlangen, Germany, EU
2   Institut für Optik, Information und Photonik, Universität Erlangen-Nürnberg - Staudtstr. 7/B2, 91058 Erlangen, Germany, EU
3   Institut für Angewandte Physik, Technische Universität Darmstadt - 64289 Darmstadt, Germany, EU

magda.stobinska@mpl.mpg.de

received 10 March 2009; accepted in final form 17 March 2009; published April 2009
published online 22 April 2009

Abstract
We propose a scheme for perfect excitation of a single two-level atom by a single photon in free space. The photon state has to match the time reversed photon state originating from spontaneous decay of a two-level system. Here, we discuss its experimental preparation. The state is characterized by a particular asymmetric exponentially shaped temporal profile. Any deviations from this ideal state limit the maximum absorption. Although perfect excitation requires an infinite amount of time, we demonstrate that there is a class of initial one-photon quantum states which can achieve almost perfect absorption even for a finite interaction time. Our results pave the way for realizing perfect coupling between flying and stationary qubits in free space thus opening a possibility for building scalable quantum networks.

PACS
42.50.Ct - Quantum description of interaction of light and matter; related experiments.
03.67.Lx - Quantum computation architectures and implementations.

© EPLA 2009