An optical lattice clock based on bosonic Sr

Nicola Poli,Guglielmo M Tino,Christopher W Oates,Marco G Tarallo,Marco Schioppo

doi:10.1109/freq.2009.5168199

Abstract

We present experimental results for an optical lattice clock operating on the 1 S 0 harr 3 P 0 transition in 88 Sr, which is excited with the technique of magnetic field-induced spectroscopy To reduce the complexity of the setup we have developed a set of new experimental techniques that greatly simplifies the clock spectroscopy in Sr atoms. First, we developed a method for finding the clock transition that removes the need for extensive frequency metrology hardware and optical frequency combs. This technique exploits a near coincidence in the atomic wavelengths of the 1 S 0 harr 3 P 0 clock and 1 S 0 harr 3 P 1 second stage cooling transitions in Sr, which are only 5 THz far apart. This coincidence enables the use of an optical (transfer) cavity to reference the frequency of the clock transition relative to that of the much stronger coolign transition Second, all laser sources in the experimental setup are based on semiconductor technology, which greatly reduces the complexity of the apparatus. With this setup, about 10 4 88 Sr atoms are trapped in a 1D lattice formed by 200 mW of radiation tuned near the magic wavelength at 813 nm. Preliminar uncertainty budget for our optical lattice clock is also presented, with particular attention to density dependent collisions, which led to an unexpectedly high signal contrast for long interaction times.

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