Absolute frequency measurement of the 1S0 - 3P0 transition of 171Yb

We report the absolute frequency measurement of the unperturbed transition 1S0 - 3P0 at 578 nm in 171Yb realized in an optical lattice frequency standard. The absolute frequency is measured 518 295 836 590 863.55(28) Hz relative to a cryogenic caesium fountain with a fractional uncertainty of 5.4x10-16 . This value is in agreement with the ytterbium frequency recommended as a secondary representation of the second in the International System of Units.Comment: This is an author-created, un-copyedited version of an article accepted for publication/published in Metrologia. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from it. The Version of Record is available online at http://dx.doi.org/10.1088/1681-7575/aa4e62. It is published under a CC BY licenc

Phase noise cancellation in polarisation-maintaining fibre links

The distribution of ultra-narrow linewidth laser radiation is an integral part of many challenging metrological applications. Changes in the optical pathlength induced by environmental disturbances compromise the stability and accuracy of optical fibre networks distributing the laser light and call for active phase noise cancellation. Here we present a laboratory scale optical (at 578 nm) fibre network featuring all polarisation maintaining fibres in a setup with low optical powers available and tracking voltage-controlled oscillators implemented. The stability and accuracy of this system reach performance levels below 1 * 10^(-19) after 10 000 s of averagingComment: This article may be downloaded for personal use only. Any other use requires prior permission of the author and AIP Publishing. The following article appeared in "Phase noise cancellation in polarisation-maintaining fibre links", Rauf et al., Review of Scientific Instruments, 89, 033103 (2018) and may be found at https://doi.org/10.1063/1.501651

Geodesy and metrology with a transportable optical clock

partially_open24openGrotti, Jacopo; Koller, Silvio; Vogt, Stefan; Häfner, Sebastian; Sterr, Uwe; Lisdat, Christian; Denker, Heiner; Voigt, Christian; Timmen, Ludger; Rolland, Antoine; Baynes, Fred N.; Margolis, Helen S.; Zampaolo, Michel; Thoumany, Pierre; Pizzocaro, Marco; Rauf, Benjamin; Bregolin, Filippo; Tampellini, Anna; Barbieri, Piero; Zucco, Massimo; Costanzo, Giovanni A.; Clivati, Cecilia; Levi, Filippo; Calonico, DavideGrotti, Jacopo; Koller, Silvio; Vogt, Stefan; Häfner, Sebastian; Sterr, Uwe; Lisdat, Christian; Denker, Heiner; Voigt, Christian; Timmen, Ludger; Rolland, Antoine; Baynes, Fred N.; Margolis, Helen S.; Zampaolo, Michel; Thoumany, Pierre; Pizzocaro, Marco; Rauf, Benjamin; Bregolin, Filippo; Tampellini, Anna; Barbieri, Piero; Zucco, Massimo; Costanzo, Giovanni A.; Clivati, Cecilia; Levi, Filippo; Calonico, David

Multiple wavelength stabilization on a single optical cavity using the offset sideband locking technique

We implemented a compact, robust, and stable device for simultaneous frequency stabilization of lasers with different wavelengths used for the cooling and trapping of Yb atoms in an optical lattice clock. The lasers at 399, 556, and 759 nm are locked to a single ultra-stable cavity using the offset sideband locking technique, a modified version of the Pound-Drever-Hall method. For the most demanding stabilization here, the 556 nm laser, this system exhibits a 300 Hz linewidth for an integration time of 80 ms. We observed a long-term drift of less than 20 kHz per day at 759 nm that is suitable for operating the lattice laser with a light shift uncertainty below 1×10-18. We successfully tested the system for operating the clock during a typical working day by simultaneously locking the three lasers to the cavity

Multiple lasers stabilization on a single three color optical cavity

We designed and implemented a simple and robust optical system for the frequency stabilization of lasers at different wavelength, used for the cooling and trapping of atoms in a Yb optical lattice clock. We used a single ultra-stable cavity to lock the frequency of three different lasers at 399 nm, 556 nm and 759 nm exploiting the offset sideband locking technique, derived from the common Pound-Drever-Hall method. A linewidth of less than 300Hz is obtained at 556 nm with a fractional frequency stability of 3 × 10−14 at 1s. At 759 nm we measured a long term drift less than 20kHz per day, which is sufficient to keep the lattice light shift fractional uncertainty under 1 × 10−18. The system was tested by simultaneously locking the three lasers to the cavity and operating the clock without any significant reduction in number of atoms

Absolute frequency measurement of the 171Yb optical lattice clock at INRIM

We present the absolute frequency measurement of the transition 1S0 - 3P0 at 578 nm in ytterbium 171 realized in an optical lattice frequency standard relative to the cryogenic caesium fountain ITCsF2. The measurement result is 518 295 836 590 863.59(31) Hz with a relative standard uncertainty of 5.9 × 10-16. A contribution of 1.6 × 10-16 is coming from the ytterbium clock and we are working to reduce this contribution to the 1 × 10-17 level