The absolute frequency of the 87 Sr optical clock transition (original) (raw)
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Applied Physics Express, 2014
We perform spectroscopic observations of the 698-nm clock transition in 87 Sr confined in an optical lattice using a laser linewidth transfer technique. A narrow-linewidth laser interrogating the clock transition is prepared by transferring the linewidth of a master laser (1064 nm) to that of a slave laser (698 nm) with a high-speed controllable fiber-based frequency comb. The Fourier-limited spectrum is observed for an 80-ms interrogating pulse. We determine that the absolute frequency of the 5s 2 1 S0 -5s5p 3 P0 clock transition in 87 Sr is 429 228 004 229 872.0 (1.6) Hz referenced to the SI second.
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.
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.
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.
Physical Review Letters, 2000
We report on an absolute frequency measurement of the hydrogen 1S-2S two-photon transition in a cold atomic beam with an accuracy of 1.8 parts in 10 14 . Our experimental result of 2 466 061 413 187 103(46) Hz has been obtained by phase coherent comparison of the hydrogen transition frequency with an atomic cesium fountain clock. Both frequencies are linked with a comb of laser frequencies emitted by a mode locked laser. 06.30.Ft, 06.20.Jr, 42.62.Fi The 1S-2S two-photon transition in atomic hydrogen has played a central role in the progress of high resolution laser spectroscopy and optical frequency metrology . It provides a cornerstone for the determination of fundamental constants such as the Rydberg constant, which has become the most precisely measured constant in physics, and the 1S-Lamb shift to yield the most stringent test of quantum electrodynamics in an atom .
Precision spectroscopy of cold strontium atoms, towards optical atomic clock
This report concerns the experiment of precision spectroscopy of cold strontium atoms in the Polish National Laboratory of Atomic, Molecular and Optical Physics in Toruń. The system is composed of a Zeeman slower and magneto-optical traps (at 461 nm and 689 nm), a frequency comb, and a narrow-band laser locked to an ultra-stable optical cavity. All parts of the experiment are prepared and the first measurements of the absolute frequency of the 1 S0-3 P1, 689 nm optical transition in 88 Sr atoms are performed.
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.
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.
Measurement of the 27Al+ and 87Sr absolute optical frequencies
Metrologia, 2021
We perform absolute measurement of the 27Al+ single-ion and 87Sr neutral lattice clock frequencies at the National Institute of Standards and Technology and JILA at the University of Colorado against a global ensemble of primary frequency standards. Over an eight month period multiple measurements yielded the mean optical atomic transition frequencies ν Al + = 1 121 015 393 207 859.50 ( 0.36 ) Hz and ν Sr = 429 228 004 229 873.19(0.15) Hz, where the stated uncertainties are dominated by statistical noise and gaps in the observation interval (‘dead-time’ uncertainty).