Stuttgart 2012 – wissenschaftliches Programm
Q 34.76: Poster
Dienstag, 13. März 2012, 16:30–19:00, Poster.I+II
Ultrastable laser system for a magnesium optical lattice clock — •Steffen Rühmann, Andre Pape, Temmo Wübbena, André Kulosa, Hrishikesh Kelkar, Dominika Fim, Klaus Zipfel, Wolfgang Ertmer, and Ernst M. Rasel — Institut für Quantenoptik, Leibniz Universität Hannover, Welfengarten 1, 30167 Hannover, Germany
Current optical clocks promise to exceed the current performance of microwave clocks. We currently upgrade our magnesium clock with an optical lattice. Ultracold magnesium atoms are captured in a magneto-optical trap and in near future in an optical lattice at the magic wavelength  for high precision spectroscopy of the ultranarrow 1S0 → 3P0 clock transition.
The frequency measurement of this sub-Hz wide transition sets stringent requirements with respect to the clock laser. For this purpose we built two independent diode laser systems @ 914 nm which are stabilized to independent high finesse resonators. The resonators are housed horizontally in a vacuum chamber and are mounted such that influence of vibrations is effiently supressed. We use mirror substrates made of fused silica setting the thermal noise floor to 3 × 10−16. We achieved a fractional instability of one cavity of 5 × 10−16 in 1 s which is comparable to the highest reported stabilities for cavity-stabilized lasers. We describe the current status and performance of our ultrastable laser systems.