Optical lattice clock with spin-polarized <formula><sup><roman>87</roman></sup></formula>Sr atoms (original) (raw)

An optical lattice clock with spin-polarized 87Sr atoms

The European Physical Journal D, 2008

We present a new evaluation of an 87 Sr optical lattice clock using spin polarized atoms. The frequency of the 1 S0 → 3 P0 clock transition is found to be 429 228 004 229 873.6 Hz with a fractional accuracy of 2.6 × 10 −15 , a value that is comparable to the frequency difference between the various primary standards throughout the world. This measurement is in excellent agreement with a previous one of similar accuracy [1]. a e-mail: pierre.lemonde@obspm.fr 1 The first order shift can be made to vanish in this type of clocks at the so-called "magic wavelength".

Accurate Optical Lattice Clock with Sr87 Atoms

Physical Review Letters, 2006

We report a frequency measurement of the 1 S0 − 3 P0 transition of 87 Sr atoms in an optical lattice clock. The frequency is determined to be 429 228 004 229 879 (5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall. Two previous measurements of this transition were found to disagree by about 2 × 10 −13 , i.e. almost four times the combined error bar, instilling doubt on the potential of optical lattice clocks to perform at a high accuracy level. In perfect agreement with one of these two values, our measurement essentially dissipates this doubt. PACS numbers: 06.30.Ft,32.80.-t,42.50.Hz,42.62.Fi 1 S 0 1 P 1 4 6 1 n m / = 3 2 M H z 3 S 1 3 P 0 6 8 9 n m / = 7 , 6 k H z 6 8 8 n m 7 0 7 n m 6 7 9 n m 6 9 8 n m / = 1 m H z 3 P 1 3 P 2 FIG. 1: Relevant energy levels of 87 Sr.

Operating a 87Sr optical lattice clock with high precision and at high density

IEEE Transactions on Ultrasonics, Ferroelectrics and Frequency Control, 2012

We describe recent experimental progress with the JILA Sr optical frequency standard, which has a systematic uncertainty at the 10 −16 fractional frequency level. An upgraded laser system has recently been constructed in our lab which may allow the JILA Sr standard to reach the standard quantum measurement limit and achieve record levels of stability. To take full advantage of these improvements, it will be necessary to operate a lattice clock with a large number of atoms, and systematic frequency shifts resulting from atomic interactions will become increasingly important. We discuss how collisional frequency shifts can arise in an optical lattice clock employing fermionic atoms and describe a novel method by which such systematic effects can be suppressed.

Accuracy Evaluation of a $^{87}\hbox{Sr}$ Optical Lattice Clock

IEEE Transactions on Instrumentation and Measurement, 2000

In this paper, we report the observation of the higher order frequency shift due to the trapping field in a 87 Sr optical lattice clock. We show that at the magic wavelength of the lattice, where the first order term cancels, the higher order shift will not constitute a limitation to the fractional accuracy of the clock at a level of 10 −18 . We also report an accurate frequency measurement of the clock transition. The frequency is determined to be ν1 S 0 − 3 P 0 = 429 228 004 229 879 (5) Hz with a fractional uncertainty that is comparable to state-of-the-art optical clocks with neutral atoms in free fall.

Systematic Study of the Sr87 Clock Transition in an Optical Lattice

Physical Review Letters, 2006

With ultracold 87 Sr confined in a magic wavelength optical lattice, we present the most precise study (2.8 Hz statistical uncertainty) to date of the 1 S 0-3 P 0 optical clock transition with a detailed analysis of systematic shifts (19 Hz uncertainty) in the absolute frequency measurement of 429 228 004 229 869 Hz. The high resolution permits an investigation of the optical lattice motional sideband structure. The local oscillator for this optical atomic clock is a stable diode laser with its hertz-level linewidth characterized by an octave-spanning femtosecond frequency comb.

Accuracy evaluation of an optical lattice clock with bosonic atoms

Optics Letters, 2007

We report the first accuracy evaluation of an optical lattice clock based on the 1 S 0 → 3 P 0 transition of an alkaline earth boson, namely 88 Sr atoms. This transition has been enabled using a static coupling magnetic field. The clock frequency is determined to be 429 228 066 418 009(32) Hz. The isotopic shift between 87 Sr and 88 Sr is 62 188 135 Hz with fractional uncertainty 5 × 10 −7 . We discuss the conditions necessary to reach a clock accuracy of 10 −17 or less using this scheme.

Development of a Strontium optical lattice clock

The ESA mission "Space Optical Clock" project aims at operating an optical lattice clock on the ISS in approximately 2023. The scientific goals of the mission are to perform tests of fundamental physics, to enable space-assisted relativistic geodesy and to intercompare optical clocks on the ground using microwave and optical links. The performance goal of the space clock is less than 1 × 10-17 uncertainty and 1 × 10-15 τ-1/2 instability. Within an EU-FP7-funded project, a strontium optical lattice clock demonstrator has been developed. Goal performances are instability below 1 × 10-15 τ-1/2 and fractional inaccuracy 5 × 10-17. For the design of the clock, techniques and approaches suitable for later space application are used, such as modular design, diode lasers, low power consumption subunits, and compact dimensions. The Sr clock apparatus is fully operational, and the clock transition in 88 Sr was observed with linewidth as small as 9 Hz.

Determination of Sr properties for a high-accuracy optical clock

Physical Review A, 2008

We have carried out calculations towards the goal of reducing the inaccuracy of the Sr optical atomic clock to 1×10 −17 and below. We calculated a.c. polarizabilities of the 5s 2 1 S0 and 5s5p 3 P o 0 clock states that are important for reducing the uncertainty of blackbody radiation-induced frequency shifts for the 1 S0 − 3 P o 0 clock transition. We determined four low-lying even-parity states whose total contribution to the static polarizability of the 3 P o 0 clock state is at the level of 90%. We show that if the contribution of these states is experimentally known with 0.1% accuracy, the same accuracy can be achieved for the total polarizability of the 3 P o 0 state. The corresponding uncertainty for the blackbody shift at a fixed room temperature will be below 1×10 −17 . The calculations are confirmed by a number of experimental measurements on various Sr properties. PACS numbers: 31.15.ac, 31.15.am, 31.15.ap, 32.70.Cs * Electronic address: sporsev@gmail.com † Present address: NIST Time and Frequency Division, Boulder, Colorado, 80309, USA 3 P o J

Sr Lattice Clock at 1 × 10 –16 Fractional Uncertainty by Remote Optical Evaluation with a Ca Clock

Science, 2008

Optical atomic clocks promise timekeeping at the highest precision and accuracy, owing to their high operating frequencies. Rigorous evaluations of these clocks require direct comparisons between them. We have realized a high-performance remote comparison of optical clocks over kilometer-scale urban distances, a key step for development, dissemination, and application of these optical standards. Through this remote comparison and a proper design of lattice-confined neutral atoms for clock operation, we evaluate the uncertainty of a strontium (Sr) optical lattice clock at the 1 × 10 –16 fractional level, surpassing the current best evaluations of cesium (Cs) primary standards. We also report on the observation of density-dependent effects in the spin-polarized fermionic sample and discuss the current limiting effect of blackbody radiation–induced frequency shifts.

A strontium lattice clock with 3 × 10−17inaccuracy and its frequency

New Journal of Physics, 2014

We have measured the absolute frequency of the optical lattice clock based on 87 Sr at PTB with an uncertainty of 3.9 × 10 −16 using two caesium fountain clocks. This is close to the accuracy of today's best realizations of the SI second. The absolute frequency of the 5s 2 1 S 0-5s5p 3 P 0 transition in 87 Sr is 429 228 004 229 873.13(17) Hz. Our result is in excellent agreement with recent measurements performed in different laboratories worldwide. We improved the total systematic uncertainty of our Sr frequency standard by a factor of five and reach 3 × 10 −17 , opening new prospects for frequency ratio measurements between optical clocks for fundamental research, geodesy, or optical clock evaluation.