Improved Frequency Measurement of a One-Dimensional Optical Lattice Clock with a Spin-Polarized Fermionic 87 Sr Isotope

Journal of the Physical Society of Japan (Impact Factor: 1.59). 08/2006; 75(10). DOI: 10.1143/JPSJ.75.104302
Source: arXiv


We demonstrate a one-dimensional optical lattice clock with a spin-polarized fermionic isotope designed to realize a collision-shift-free atomic clock with neutral atom ensembles. To reduce systematic uncertainties, we developed both Zeeman shift and vector light-shift cancellation techniques. By introducing both an H-maser and a Global Positioning System (GPS) carrier phase link, the absolute frequency of the $^1S_0(F=9/2) - {}^3P_0(F=9/2)$ clock transition of the $^{87}$Sr optical lattice clock is determined as 429,228,004,229,875(4) Hz, where the uncertainty is mainly limited by that of the frequency link. The result indicates that the Sr lattice clock will play an important role in the scope of the redefinition of the ``second'' by optical frequency standards. Comment: 10pages, 10 figures, submitted to J. Phys. Soc. Jpn

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Available from: H. Katori, Nov 05, 2013
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    • "In this sense the Sr lattice optical clock seems to be the most promising, for two main reasons: 1) all the needed lights for the clock operation (cooling, repumping, clock and lattice laser) can be produced by semiconductor lasers [8] [9] [10] [11] [12] (see Fig.1), 2) the Sr lattice clock is the most mature in therms of technology and scientific results with many under development around the world. In a recent demonstration, a Sr lattice clock achieved a fractional short term instability of 10 −15 for an averaging time of 1 s [13] [14] [15] and an absolute fractional frequency uncertainty of 10 −17 [16]. "
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    ABSTRACT: We presented the first prototype of transportable laser-cooled strontium source. Novel design solutions have been discussed with a final volume, mass and power consumption budget for the atomic-package of 210 liters, 120 kg and 110 W, respectively. Most of the home made components have been assembled and tested. The system is currently under characterization and it is already able to produce a sample of about 108 atoms at 1 mK temperature. Next steps will be the integration of this system with a second stage cooling laser and with a transportable clock laser in order to realize a fully transportable optical lattice clock. Technical solutions, methods and know-how developed in this work will be used to built more robust, compact and advanced technology apparatus, with the nal aim to provide specifications for a future space optical lattice clock.
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    • "It is also applied in weighting each clock for computing International Atomic Time (TAI) [2]. In developing optical clocks, the absolute frequency of the clock is determined by calculating the weighted mean of the measured frequency of the clock transition [3] [4] [5]. The ultimate accuracy limit of the optical frequency comb (OFC) technique has been tested by frequency comparisons among OFCs utilizing the uncertainty associated with the weighted mean of the frequency difference between the OFCs [6] [7] [8] [9] [10] [11] [12] [13]. "
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    ABSTRACT: The weighted mean is widely used in combining data sets of experimental measurements with a weight proportional to the value of the data number divided by the sample variance in a conventional method. However, this standard procedure is not appropriate for obtaining the weighted mean frequency of a phase-stabilized signal with white phase noise, since the data are autocorrelated. The autocorrelation is obtained in the case of white phase noise and a new weighting method is proposed. Using this, the uncertainty associated with the weighted mean frequency of a phase-stabilized signal with white phase noise is given. The effect of counter dead-time is also discussed.
    Metrologia 12/2009; 47(1):24. DOI:10.1088/0026-1394/47/1/004 · 2.04 Impact Factor
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    • "ptical lattice clocks with strontium have reached relative uncertainties below 10 -15 [4] [5] [6]. Their stability is ultimately limited by the quantum projection noise which for uncorrelated 10 6 atoms and a Fourier-limited linewidth of 1 Hz would result in an Allan deviation of the relative frequency fluctuations of σ y (τ) ≈ 10 -18 · τ -1/2 . "
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    ABSTRACT: We report on the setup and characterization of a 698-nm master-slave diode laser system to probe the <sup>1</sup>S<sub>0</sub>-<sup>3</sup>P<sub>0</sub> clock transition of strontium atoms confined in a 1-D optical lattice. A linewidth on the order of about 100 Hz of the laser system has been measured with respect to an ultrastable 657-nm diode laser with 1-Hz linewidth using a femtosecond fiber comb as a transfer oscillator. The laser has been used to measure the magnetically induced <sup>1</sup>S<sub>0</sub>-<sup>3</sup>P<sub>0</sub> clock transition in <sup>88</sup>Sr, where a linewidth of 165 Hz has been observed. The transfer oscillator method provides a virtual beat signal between the two diode lasers that has been used to phase lock the 698-nm laser to the 1-Hz-linewidth laser at 657 nm, transferring its stability to the 698-nm laser system.
    IEEE Transactions on Instrumentation and Measurement 04/2009; 58(4):1252-1257. DOI:10.1109/TIM.2008.2007042 · 1.79 Impact Factor
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