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Sub-recoil clock-transition laser cooling enabling shallow optical lattice clocks



Xiaogang Zhang, Kyle Beloy, Youssef Hassan, William McGrew, Chun-Chia Chen, Jacob Siegel, Tanner Grogan, Andrew Ludlow


Laser cooling is a key ingredient for quantum control of atomic systems in a variety of settings. In two-valence-electron atoms, two-stage Doppler cooling is typically used to bring atoms to the μK regime. Here, we implement a pulsed radial cooling scheme using the ultranarrow 1S0-3P0 clock transition in ytterbium to realize sub-recoil temperature, down to tens of nK. Together with sideband cooling along the one-dimensional lattice axis, we efficiently prepare atoms in shallow lattices at 6 lattice recoil energy. Under these conditions, key limits on lattice clock accuracy and stability are reduced, opening the door to dramatic improvements. Furthermore, Bloch oscillations in the shallow lattice do not compromise clock accuracy at the 10-19 level.
Physical Review Letters


Zhang, X. , Beloy, K. , Hassan, Y. , McGrew, W. , Chen, C. , Siegel, J. , Grogan, T. and Ludlow, A. (2022), Sub-recoil clock-transition laser cooling enabling shallow optical lattice clocks, Physical Review Letters, [online],, (Accessed April 23, 2024)
Created September 8, 2022, Updated March 26, 2024