Search

We report a stability below $7\times 10{}^{-17}$ of two independent optical lattice clocks operating with bosonic ${}^{88}$Sr isotope. The value (429228066418008.3(1.9)${}_{syst}$(0.9)${}_{stat}$~Hz) of the absolute frequency of the ${}^{1}S_{0}$ - ${}^{3}P_{0}$ transition was measured with an optical frequency comb referenced to the local representation of the UTC by the 330 km-long stabilized fibre optical link. The result was verified by series of measurements on two independent optical lattice clocks and agrees with recommendation of Bureau International des Poids et Mesures.

A low-cost, stand-alone Global-Positioning-System-time-synchronized data acquisition system is described. The constructed prototype allows recoding up to four analog signals with a 16-bit resolution in variable ranges and a maximum sampling rate of 1000 S/s. Additionally, two digital readouts of external sensors can be acquired. A complete data set is stored on a Secure Digital (SD) card or transmitted to a computer using Universal Serial Bus (USB). The estimated time accuracy of the data acquisition is better than 0.2 {\mu}s. The device is envisioned for the use in a global distributed sensor network (the Global Network of Optical Magnetometers for Exotic physics - GNOME), whose aim is to search for new particles and interactions.

Optical magnetometers are currently able to achieve magnetometric sensitivities below 1 fT/Hz^1/2. Although such sensitivities are typically obtained for ultra-low-field measurements, a group of optical magnetometers allows the detection of the fields in much broader dynamic range without a significant compromise in the sensitivity. A particular example of such a device is the magnetometer exploiting amplitude-modulated nonlinear magneto-optical rotation. It enables to measure a magnetic field via detection of a polarization state of light traversing a medium subjected to the field. In this paper, an electronic-circuit analogue of such the magnetometer is elaborated. Its operation is investigated with an electronic-circuit design software, which allows to study the "magnetometer" performance as a function of various parameters. The ability to automate operation of the magnetometer and automatically track "magnetic field" is demonstrated. The simulations are verified with experimental results obtained with the magnetometer operating in one of the investigated arrangements., Comment: 17 pages, 12 figures, submitted to Journal of Instrumentation