Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 41: Precision Measurement and Metrology 1
Q 41.2: Vortrag
Mittwoch, 16. März 2011, 16:45–17:00, HÜL 386
Optical Lattice Clock with 87Sr — •Stephan Falke, Thomas Middelmann, Fritz Riehle, Uwe Sterr, and Christian Lisdat — Physikalisch-Technische Bundesanstalt (PTB), Bundesallee 100, 38116 Braunschweig, Germany
We present an absolute frequency measurement of the 5s2 1S0 –5s5p 3P0 transition of 87Sr against the Cs fountain clock CsF1 at PTB. An ultrastable laser with a linewidth of about 1 Hz interrogates an ensemble of ultracold fermionic strontium atoms that are held in an optical lattice. The lattice laser is set to the magic wavelength at 813 nm. The trapping allows for Doppler-free spectroscopy and interrogation times of 90 ms. The interrogating laser is locked to the atoms by measuring the transition probability for the two extreme Zeeman components that show a Fourier linewidth of 10 Hz.
The systematics of the Sr system itself has been investigated using an alternating stabilization technique. It is found to be better than, both, the systematic and the statistical uncertainty of the Cs clock.
With the alternating stabilization scheme, we measured the magic wavelength for the optical lattice. This frequency is determind to the level of a few MHz.
By comparing the transition frequency for different densities we looked for the effect of collisions (density shift). Such shifts can at least be reduced to 3 × 10−17 for our experimental configuration.
The work is supported by the Centre for Quantum Engineering and Space-Time Research (QUEST), ESA, DLR, and the ERA-NET Plus Programme.