Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 54: Quantum Effects: QED
Q 54.3: Vortrag
Donnerstag, 17. März 2011, 15:00–15:15, SCH A01
Observation of the Collective Lambshift in Single-Photon Superradiance — •Ralf Röhlsberger1, Kai Schlage1, Balaram Sahoo1, Sebastien Couet2, and Rudolf Rüffer3 — 1DESY, Notkestr. 85, 22607 Hamburg — 2KU Leuven, Celestijnenlaan 200D, 3001 Leuven, Belgium — 3ESRF, 38043 Grenoble Cedex, France
The interaction of many identical two-level atoms with a common radiation field leads to a profound modification of the temporal, directional and spectral characteristics of their collective emission compared to that of a single atom. A prominent example is the phenomenon of superradiance that manifests as a strong acceleration of the collective spontaneous emission [1]. Later it was predicted that the superradiant emission goes along with a radiative shift of the transition energy, the collective Lamb shift (CLS) [2,3]. In the optical regime, however, this shift appeared to be extremely difficult to observe due to its small magnitude and atom-atom interactions masking it. In the x-ray regime, these effects can be neglected. Thus, we used pulsed 14.4 keV synchrotron radiation to resonantly excite ensembles of 57Fe Mössbauer atoms into a purely superradiant state [4]. For that purpose the atoms were embedded into a planar solid-state cavity. Spectral analysis of the cooperative emission revealed the CLS as predicted. Applications for the analysis of cooperative emission in general will be discussed.
[1] R. H. Dicke, Phys. Rev. 93, 99 (1954). [2] R. Friedberg, S. R. Hartmann, and J. T. Manassah, Phys. Rep. C 7, 101 (1973). [3] M. O. Scully, Phys. Rev. Lett. 102, 143601 (2009). [4] R. Röhlsberger, K. Schlage, B. Sahoo, S. Couet and R. Rüffer, Science 328, 1248 (2010).