Berlin 2014 – wissenschaftliches Programm
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Q: Fachverband Quantenoptik und Photonik
Q 16: Poster: Quantum information, micromechanical oscillators, matter wave optics, precision measurements and metrology
Q 16.73: Poster
Montag, 17. März 2014, 16:30–18:30, Spree-Palais
Ultra-low frequency-noise laser for reducing the instability of an optical lattice clock — •S. Häfner1, St. Falke1, M. Merimaa2, Ch. Grebing1, Th. Legero1, Ch. Lisdat1, and U. Sterr1 — 1Physikalisch-Technische Bundesanstalt (PTB); Bundesallee 100; 38116 Braunschweig — 2Centre for Metrology and Accreditation (MIKES); P.O. Box 9; FI-02151 Espoo; Finland
Ultra-stable lasers are key instruments of many experiments in physics, e.g. optical clocks use low-noise lasers to interrogate narrow atomic reference transitions. State-of-the-art lasers reach a relative frequency instability of just below 10−16 at a few seconds averaging time by frequency locking to an external reference cavity. The frequency noise of reference cavities is limited by Brownian motion in the mirror coatings and substrates and scales inversely proportional to the length of the cavity. In the presented work, we have used a 48-cm long spacer with an estimated thermal noise limited instability of 4×10−17. This ultra-stable laser was evaluated in a three-cornered-hat comparison and in PTB’s strontium lattice clock. We observed a minimum laser instability of 7×10−17 at 300 s and an improved stability of the optical clock down to an estimated 4×10−16 √s/τ. This reduces averaging times in studies of systematic shifts of the clock transition frequency and places our clock among the most stable clocks worldwide.
This work was supported by QUEST, DFG (RTG 1729), and the European Metrology Research Programme (EMRP) in IND14, ITOC, and QESOCAS. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union.