Precision meets portability
Summarize this article with:
Subjects Optical metrologyOptical spectroscopy Access through your institution Buy or subscribe In all atomic clocks, time is measured using a well-defined transition between atomic energy levels. In their work, Offer and colleagues interrogated an ultra-narrow optical transition in ytterbium. In most optical clocks, accessing such narrow transitions requires the atoms to be immobilized in an optical lattice to suppress Doppler broadening and sharpen the resonance. That in turn necessitates multiple cooling and trapping lasers, as well as a complex vacuum system, resulting in bulky infrastructure ill-suited for transportation.The design by Offer and colleagues circumvents this complexity by using a thermal ytterbium atomic beam. Although the atoms remain in motion, their velocity is laser-cooled in only one direction, perpendicular to the beam. This transverse cooling enables access to the ultra-narrow clock resonance without the need for full three-dimensional laser cooling, which would hinder portability.
The team interrogated the transition using Ramsey–Bordé spectroscopy, in which counter-propagating laser pulses split and recombine the atomic wavefunction to form a matter-wave interferometer that compares the clock laser frequency with the atomic transition. This is a preview of subscription content, access via your institution Access options Access through your institution Access Nature and 54 other Nature Portfolio journals Get Nature+, our best-value online-access subscription $32.99 / 30 days cancel any time Learn more Subscribe to this journal Receive 12 print issues and online access $259.00 per year only $21.58 per issue Learn more Rent or buy this article Prices vary by article type from$1.95 to$39.95 Learn more Prices may be subject to local taxes which are calculated during checkout Author informationAuthors and AffiliationsNature Physics https://www.nature.com/nphys/Sonal MistryAuthorsSonal MistryView author publicationsSearch author on:PubMed Google ScholarCorresponding authorCorrespondence to Sonal Mistry.Rights and permissionsReprints and permissionsAbout this articleCite this articleMistry, S. Precision meets portability. Nat. Phys. (2026). https://doi.org/10.1038/s41567-026-03313-4Download citationPublished: 15 May 2026Version of record: 15 May 2026DOI: https://doi.org/10.1038/s41567-026-03313-4Share this articleAnyone you share the following link with will be able to read this content:Get shareable linkSorry, a shareable link is not currently available for this article.Copy shareable link to clipboard Provided by the Springer Nature SharedIt content-sharing initiative