NOTICE: Due to a lapse in annual appropriations, most of this website is not being updated. Learn more.
Form submissions will still be accepted but will not receive responses at this time. Sections of this site for programs using non-appropriated funds (such as NVLAP) or those that are excepted from the shutdown (such as CHIPS and NVD) will continue to be updated.
An official website of the United States government
Here’s how you know
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you’ve safely connected to the .gov website. Share sensitive information only on official, secure websites.
Xiaogang Zhang, Kyle Beloy, Youssef Hassan, William McGrew, Chun-Chia Chen, Jacob Siegel, Tanner Grogan, Andrew Ludlow
Abstract
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.
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], https://doi.org/10.1103/PhysRevLett.129.113202, https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=934445
(Accessed October 6, 2025)