Scientific Reports

Carrier thermometry of cold ytterbium atoms in an optical lattice clock

Chengyin Han, Min Zhou, Xiaohang Zhang, Qi Gao, Yilin Xu, Shangyan Li, Shuang Zhang, Xinye Xu

Published May 15, 2018• 8 citations

Abstract

The ultracold atomic gas serving as the quantum reference is a key part of an optical lattice clock, and the temperature of atoms in the optical lattice affects the uncertainty and instability of the optical lattice clocks. Since the carrier spectrum of the clock transition in the lattices reflects the thermal dynamics of cold atoms, the temperature of atoms can be extracted from the carrier spectrum in a non-magic wavelength lattice of ytterbium optical clocks. Furthermore, the temperatures obtained from the carrier spectra are in good agreement with the results obtained by the time-of-flight method and thermometry based on the sideband spectrum. In addition, the heating effects caused by the lattice laser are studied on the basis of the sample temperatures.

DOI: 10.1038/s41598-018-26367-8

Related papers

Thermal dynamics of cold atoms in171Yb optical lattice clocks

Chengyin Han, Min Zhou, Xiaohang Zhang +6 more

The ultracold atoms served as quantum references is a key part of optical lattice clocks, and the thermal dynamics of the atoms in the optical lattice affects the uncertainty and stability of the lattice clocks. Since the carrier spectrum of clock transition in lattices reflects the thermal dynamics of cold atoms, we can obtain the temperature of atoms by measuring the carrier spectrum in171Yb optical lattice clocks. Furthermore we find that the temperatures obtained from the carrier spectra are in a good agreement with the results obtained by using methods of time-of-flight and thermometry based on sideband spectrum. In addition, we study the heating effects caused by the lattice laser in ytterbium optical lattice clocks.

Joint Conference of the European Frequency and Time Forum and IEEE International Frequency Control Symposium (EFTF/IFCS)May 1, 20160 citations

Analysis of uncertainties of a cold-ytterbium atomic frequency standard using operational parameters of its optical lattice

Anastasia V. Semenko, G S Belotelov, Denis V. Sutyrin +5 more

Abstract We have assessed the effect of optical lattice laser field parameters (polarisation, intensity, and wavelength) of a cold-ytterbium atomic frequency standard on the systematic uncertainty of precision clock transition frequency measurements. The spectrum and polarisation of the laser field of the lattice have been investigated in detail directly in the spatial region of interaction of cold ytterbium atoms with the laser field. The Stark shift of the clock transition in the vicinity of the magic wavelength of the laser has been estimated as a function of the experimentally measured laser field intensity in the dipole approximation. The estimates have been used to calculate the residual systematic uncertainty in the light shift of the optical lattice laser frequency.

Quantum ElectronicsMay 19, 20212 citations

Rydberg Spectroscopy in an Optical Lattice: Blackbody Thermometry for Atomic Clocks

Vitalii D Ovsiannikov, Andrei Derevianko, Kurt Gibble

We show that optical spectroscopy of Rydberg states can provide accurate in situ thermometry at room temperature. Transitions from a metastable state to Rydberg states with principal quantum numbers of 25-30 have 200 times larger fractional frequency sensitivities to blackbody radiation than the strontium clock transition. We demonstrate that magic-wavelength lattices exist for both strontium and ytterbium transitions between the metastable and Rydberg states. Frequency measurements of Rydberg transitions with 10(-16) accuracy provide 10 mK resolution and yield a blackbody uncertainty for the clock transition of 10(-18).

arXiv:1107.3169Physical Review LettersAug 23, 201163 citations

Analysis of inhomogeneous-excitation frequency shifts of ytterbium optical lattice clocks

Ning Chen, Xinye Xu

We have investigated the frequency shifts caused by inhomogeneous excitation in a 171Yb optical lattice clock. The dependences of the inhomogeneity on the temperature of the cold ytterbium atoms and the misaligning angle between the lattice laser and the clock laser are analyzed by numerical calculations. The dependence of the fractional collisional frequency shift on the ground state fraction under different cold atom temperatures, atom numbers, lattice trap depths and unequal transverse and longitudinal temperatures are also shown. The results show that the uncertainty of the ytterbium clocks, contributed by the inhomogeneous excitation, can be reduced to be 10−19 or even lower with certain conditions.

Laser Physics LettersNov 28, 20143 citations

Thermometry via Light Shifts in Optical Lattices

Mickey McDonald, B. H. McGuyer, G. Z. Iwata +1 more

For atoms or molecules in optical lattices, conventional thermometry methods are often unsuitable due to low particle numbers or a lack of cycling transitions. However, a differential spectroscopic light shift can map temperature onto the line shape with a low sensitivity to trap anharmonicity. We study narrow molecular transitions to demonstrate precise frequency-based lattice thermometry, as well as carrier cooling. This approach should be applicable down to nanokelvin temperatures. We also discuss how the thermal light shift can affect the accuracy of optical lattice clocks.

arXiv:1409.5852Physical Review LettersJan 14, 201539 citations

Optical Lattice Clock with Spin-1/2 Ytterbium Atoms

N. Lemke

An optical lattice clock probes a spectrally narrow electronic transition in an ensemble of optically trapped, laser-cooled atoms, for use as a time and frequency standard. To date, several lattice clocks have been demonstrated with superior stability and accuracy compared to primary frequency standards based on microwave transitions. Yet, the question of which atomic system (including the element and isotope) performs best as a lattice clock remains unsettled. This thesis describes the first detailed investigation of an optical lattice clock using a spin-1/2 isotope of the ytterbium atom. A spin-1/2 system possesses several advantages over higher-spin systems, including a simplified level structure (allowing for straightforward manipulation of the nuclear spin state) and the absence of any tensor light shift from the confining optical lattice. Moreover, the ytterbium atom (Yb) stands among the leading lattice clock candidates, offering a high-performance optical clock with some degree of experimental simplicity. The frequency stability of the Yb clock is highlighted by resolving an ultra-narrow clock spectrum with a full-width at half-maximum of 1 Hz, corresponding to a record quality factor Q = ν0/Δν = 5 × 1014. Moreover, this system can be highly accurate, which is demonstrated by characterizing the Yb clock frequency at the 3 × 10-16 level of fractional uncertainty, with further progress toward a ten-fold improvement also presented. To reach this low level of uncertainty required careful consideration of important systematic errors, including the identification of the Stark-canceling wavelength, where the clock’s sensitivity to the lattice intensity is minimized, a precise determination of the static polarizability of the clock transition, and the measurement and control of atom-atom collisions.

Jan 1, 20127 citations