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Licensed Unlicensed Requires Authentication Published by De Gruyter September 7, 2019

Towards a compact, optically interrogated, cold-atom microwave clock

Rachel Elvin, Michael W. Wright, Ben Lewis, Brendan L. Keliehor, Alan Bregazzi, James P. McGilligan, Aidan S. Arnold, Paul F. Griffin and Erling Riis


A compact platform for cold atoms opens a range of exciting possibilities for portable, robust and accessible quantum sensors. In this work, we report on the development of a cold-atom microwave clock in a small package. Our work utilises the grating magneto-optical trap and high-contrast coherent population trapping in the linlin polarisation scheme. We optically probe the atomic ground-state splitting of cold 87Rb atoms using a Ramsey-like sequence whilst the atoms are in free-fall. We have measured a short-term fractional frequency stability of 5×1011/τ with a projected quantum projection noise limit at the 1013/τ level.

Corresponding author: Rachel Elvin, SUPA, University of Strathclyde, G4 0NG Glasgow, UK,

Funding source: Engineering and Physical Sciences Research Council

Award Identifier / Grant number: EP/M013294/1

Award Identifier / Grant number: EP/T001046/1

Funding source: Defence Science and Technology Laboratory

Award Identifier / Grant number: DSTLX1000138605


The authors gratefully thank Dr. Greg Hoth for his excellent work and support in driving the project.

  1. Author contributions: All authors have accepted responsibility for the entire content of this manuscript and approved its submission.

  2. Research funding: The authors acknowledge financial support from EPSRC through the UK Quantum Technology Hub for Sensors and Metrology/Timing (EP/M013294/1, EP/T001046/1) and from the Defence Science and Technology Laboratory (DSTLX1000138605). The data supporting this publication can be accessed at:

  3. Competing interests: Authors state no conflict of interest.


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Received: 2020-05-29
Accepted: 2020-07-07
Published Online: 2019-09-07
Published in Print: 2020-11-26

© 2020 Walter de Gruyter GmbH, Berlin/Boston

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