Dresden 2011 – scientific programme
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Q: Fachverband Quantenoptik und Photonik
Q 23: Poster 2: Intersectional Session
Q 23.57: Poster
Tuesday, March 15, 2011, 18:00–21:00, P1
Probing the Wigner function of pulsed single photons point-by-point — Kaisa Laiho1, •Georg Harder2, Katiuscia N. Cassemiro1, David Gross3, and Christine Silberhorn1,2 — 1MPI for the Science of Light, Erlangen, Germany — 2Applied Physics, University of Paderborn, Germany — 3Institute for Theoretical Physics, ETH Zürich, Switzerland
Quantum tomography is essential in different quantum optical applications. The standard technique, homodyne detection, allows the characterization of quantum states and processes in terms of the Wigner function. However, the determination of the properties at a single point in phase space with homodyne detection requires tomographical reconstruction, since the Heisenberg’s uncertainty principle precludes the simultaneous measurement of non-commuting field quadratures.
Nevertheless, the evaluation of the Wigner function point-by-point is possible by measuring the mean value of parity operator. An all optical implementation of this direct probing scheme requires a realization of displacement operator and photon counter. We have implemented this scheme and measured the phase-averaged Wigner function of spectrally broadband, pulsed single photons at individual points in phase space [1]. Our results verify the non-classicality of the prepared single-photon state. Since the measurement is sensitive to all signal modes, it can uncover the single-mode properties of the signal in spatiotemporal degrees of freedom. Furthermore, it allows us to directly investigate the statistics of displaced states.
[1] K. Laiho, et al., Arxiv:1010.1208 (2010)