An Optical Clock Based on a Single Trapped Hg+ Ion

Published

January 1, 2001

Author(s)

Scott A. Diddams, T Udem, K R. Vogel, Christopher W. Oates, E A. Curtis, W D. Lee, Wayne M. Itano, Robert E. Drullinger, James C. Bergquist, Leo W. Hollberg

Abstract

Microwave atomic clocks have been the de facto standards for precision time and frequency metrology over the past 50 years, finding widespread use in basic scientific studies, communications, and navigation. However, with its higher operating frequency, an atomic clock based on an optical transition can be much more stable. We demonstrate an all-optical atomic clock referenced to the 1.064-petahertz transition of a single trapped ^199Hg^+ ion. A clockwork based on a mode-locked femtosecond laser provides output pulses at a 1-gigahertz rate that are phase-coherently locked to the optical frequency. By comparison to a laser-cooled calcium optical standard, an upper limit for the fractional frequency instability of 7 x 10^-15 is measured in 1 second of averaging-a value substantially better than that of the world's best microwave atomic clocks.

Citation

Science

Volume

293

Pub Type

Journals

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Citation

Diddams, S. , Udem, T. , Vogel, K. , Oates, C. , Curtis, E. , Lee, W. , Itano, W. , Drullinger, R. , Bergquist, J. and Hollberg, L. (2001), An Optical Clock Based on a Single Trapped Hg⁺ Ion, Science, [online], https://tsapps.nist.gov/publication/get_pdf.cfm?pub_id=104898 (Accessed October 22, 2025)