Dresden 2011 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 57: Poster 3: Quantengase, Ultrakalte Atome, Ultrakalte Moleküle, Materiewellen Optik, Präzisionsmessungen, Metrologie
Q 57.88: Poster
Donnerstag, 17. März 2011, 16:30–19:30, P1
Avoiding blackbody radiation shifts, density shifts, and fiber-induced laser degradation in an optical lattice clock — •Thomas Middelmann, Stephan Falke, Stefan Vogt, Fritz Riehle, Uwe Sterr, and Christian Lisdat — Physikalisch-Technische Bundesanstalt, Bundesallee 100, 38116 Braunschweig
With our recent frequency measurement of the 1S0 – 3P0 transition of 87Sr we reached a level of precision that opens the demand for investigations of the blackbody radiation shift. The blackbody radiation of the ambient housing at 300 K causes a shift of 5× 10−15 and the correction leaves an uncertainty of 1.6× 10−16 due to uncertainty of the temperature sensitivity coefficient and incomplete characterization of the environmental temperature. We will present the status of our experiments aiming at measuring the coefficient and to work at 77 K.
In current optical lattice clock experiments inhomogeneous excitation makes fermions distinguishable and thus collision shifts are observed. An imperfect alignment or wave front distortion of the clock laser beam causes motional state-dependent Rabi frequencies leading to motional state-dependent superposition states. The atoms lose their initial indistinguishability and are subject to s-wave collisions. By controlling the inhomogeneity of the excitation we investigate this effect.
Moreover, a fiber length stabilization was applied for the spectroscopy pulse to ensure that no significant frequency chirps occur during the 90 ms spectroscopy pulse. The work is supported by the Centre for Quantum Engineering and Space-Time Research (QUEST), ESA, DLR, and the ERA-NET Plus Programme.