Frequency Measurements of Al+ and Hg+ Optical Standards

Published

June 8, 2009

Author(s)

Wayne M. Itano, James C. Bergquist, Till P. Rosenband, David J. Wineland, David Hume, Chin-wen Chou, Steven R. Jefferts, Thomas P. Heavner, Tom Parker, Scott Diddams, Tara Fortier

Abstract

Frequency standards based on narrow optical transitions in 27Al+ and 199Hg+ ions have been developed at NIST. Both standards have absolute reproducibilities of a few parts in 10¹⁷. This is about an order of magnitude better than the fractional uncertainty of the SI second, which is based on the 133Cs hyperfine frequency. Use of femtosecond laser frequency combs makes it possible to compare the optical frequency standards to microwave frequency standards or to each other. The ratio of the Al+ and Hg+ frequencies can be measured more accurately than the reproducibility of the primary cesium frequency standards. Frequency measurements made over time can be used to set limits on the time variation of fundamental constants, such as the fine structure constant alpaha} or the quark masses.

Proceedings Title

Proc. 2009 ICOLS Conference

Conference Dates

June 7-13, 2009

Conference Location

Hokkaido, JP

Pub Type

Conferences

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Keywords

aluminum ion, mercury ion, optical frequency standards, time variation of fundamental constants, trapped ion frequency standards

Citation

Itano, W. , Bergquist, J. , Rosenband, T. , Wineland, D. , Hume, D. , Chou, C. , Jefferts, S. , Heavner, T. , Parker, T. , Diddams, S. and Fortier, T. (2009), Frequency Measurements of Al+ and Hg+ Optical Standards, Proc. 2009 ICOLS Conference, Hokkaido, JP, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=903328 (Accessed October 9, 2025)