Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Log inSign up
Challenges
Datasets
Workspaces
Papers
Discussions
Leaderboard
Blog
Job Board
Q3AS

© 2026 Aqora Quantum S.A.S.

TermsPrivacyLegal Notice

European Quantum Electronics Conference (EQEC)

An Optical Clock Based on Cold CA Atoms

F. Riehle, H. Schnatz, B. Lipphardt, Tilmann Trebst, G. Zinner, J. Helmcke

Published Aug 24, 2005• 0 citations
Publisher
DOI
10.1109/eqec.1998.715174

Related papers

Ultrastable optical clock with two cold-atom ensembles

M. Schioppo, Roger C. Brown, William F. McGrew +10 more

arXiv:1607.06867•Nature Photonics•Nov 28, 2016•385 citations

An improved optical clock with ultracold calcium atoms

Tatiana Nazarova, C. Degenhardt, Christian Lisdat +3 more

Conference on Lasers and Electro-Optics•Jan 1, 2005•0 citations

Nanosecond Ramsey spectroscopy for Ca beam optical clocks

Jingming Chen, Tianyu Liu, Jie Miao +6 more

Atomic beam optical clocks offer continuous operation, simplified structure, and excellent short- to mid-term stability, making them promising candidates for next-generation optical flywheel clocks. However, the atomic utilization efficiency in current thermal beam optical clocks remains below 1%, limiting their further performance enhancement. Therefore, maximizing the utilization of atoms within the atomic beam has become a critical problem. In this work, we propose an innovative nanosecond Ramsey spectroscopy for Ca beam optical clocks, which enables the full utilization of atoms with all transverse velocities. The spectral amplitude is enhanced 2300 times compared to conventional Ca beam optical clocks, and the frequency stability can reach the quantum projection noise limit of $$1.2\times 1{0}^{-17}/\sqrt{\tau }$$ in theory, comparable to the best cold-atom optical clocks. This approach paves the way for high-precision, transportable flywheel optical clocks.

npj Quantum Information•Nov 11, 2025•0 citations

Reducing statistical noise in frequency ratio measurement between Ca + and Sr optical clocks with a frequency-synthesized local oscillator from a Sr optical clock

Haosen Shi, BINGKUN LU, Huaqing Zhang +12 more

Optical frequency ratio measurement between optical atomic clocks is essential to precision measurement as well as the redefinition of the second. Currently, the statistical noise in frequency ratio measurement of most ion clocks is limited by the frequency instability of ion clocks. In this work, we reduce the statistical noise in the frequency ratio measurement between a transportable Ca + optical clock and a Sr optical lattice clock down to 2.2×10 −15 / τ . The local oscillator of the Ca + optical clock is frequency-synthesized from the Sr optical lattice clock, enabling a longer probe time for Ca + clock transition. Compared to previous measurement using independent local oscillators, we achieve 10-fold reduction in comparison campaign duration.

Photonics Research•Sep 23, 2024•5 citations

An optical atomic clock based on a highly charged ion

S. A. King, Lukas J. Spieß, P. Micke +9 more

arXiv:2205.13053•Nature•Nov 2, 2022•130 citations

Improvement of Stability of 40 Ca + Optical Clock with State Preparation

Mengyan Zeng, Yao Huang, H. Shao +5 more

Stability is one of most important performances of an atomic clock. Here we describe our recent work on improving the stability of our 40 Ca + optical clock. State preparation is adopted to transfer the ion to the ground-state magnetic sublevel of the clock transition, after the quenching laser transfers the ion to the ground state at each cycle. Using this method, the stability for 40 Ca + optical clock is improved to about . Compared with in previous work, the averaging time is decreased to reach a given level of statistical uncertainty in a clock comparison .

Chinese Physics Letters•Jul 1, 2018•6 citations
Atomic beam optical clocks offer continuous operation, simplified structure, and excellent short- to mid-term stability, making them promising candidates for next-generation optical flywheel clocks. However, the atomic utilization efficiency in current thermal beam optical clocks remains below 1%, limiting their further performance enhancement. Therefore, maximizing the utilization of atoms within the atomic beam has become a critical problem. In this work, we propose an innovative nanosecond Ramsey spectroscopy for Ca beam optical clocks, which enables the full utilization of atoms with all transverse velocities. The spectral amplitude is enhanced 2300 times compared to conventional Ca beam optical clocks, and the frequency stability can reach the quantum projection noise limit of 1.2×10−17/τ1.2\times 1{0}^{-17}/\sqrt{\tau }1.2×10−17/τ​ in theory, comparable to the best cold-atom optical clocks. This approach paves the way for high-precision, transportable flywheel optical clocks.
Optical frequency ratio measurement between optical atomic clocks is essential to precision measurement as well as the redefinition of the second. Currently, the statistical noise in frequency ratio measurement of most ion clocks is limited by the frequency instability of ion clocks. In this work, we reduce the statistical noise in the frequency ratio measurement between a transportable Ca + optical clock and a Sr optical lattice clock down to 2.2×10 −15 / τ . The local oscillator of the Ca + optical clock is frequency-synthesized from the Sr optical lattice clock, enabling a longer probe time for Ca + clock transition. Compared to previous measurement using independent local oscillators, we achieve 10-fold reduction in comparison campaign duration.
Stability is one of most important performances of an atomic clock. Here we describe our recent work on improving the stability of our 40 Ca + optical clock. State preparation is adopted to transfer the ion to the ground-state magnetic sublevel of the clock transition, after the quenching laser transfers the ion to the ground state at each cycle. Using this method, the stability for 40 Ca + optical clock is improved to about . Compared with in previous work, the averaging time is decreased to reach a given level of statistical uncertainty in a clock comparison .