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Measurement of the 27Al+ and 87Sr absolute optical frequencies



Holly Leopardi, Kyle Beloy, Tobias B. Bothwell, Samuel M. Brewer, Sarah L. Bromley, Jwo-Sy Chen, Scott Diddams, Robert J. Fasano, Youssef S. Hassan, David B. Hume, Dhruv Kedar, Colin J. Kennedy, Isaac H. Khader, David R. Leibrandt, Andrew D. Ludlow, William F. McGrew, William R. Milner, Daniele Nicolodi, Eric Oelker, Thomas E. Parker, John M. Robinson, Stefania Romisch, Jeffrey A. Sherman, Lindsay I. Sonderhouse, William C. Swann, Jian Yao, Jun Ye, Xiaogang Zhang, Tara M. Fortier


We perform absolute measurement of the 27Al+ single-ion and 87Sr neutral lattice clock frequencies at the National Institute of Standards and Technology and JILA at the University of Colorado against a global ensemble of primary frequency standards. Over an eight month period multiple measurements yielded the mean optical atomic transition frequencies nu_Al+ = 1,121,015,393,207,859.50(0.36) Hz and nu_Sr = 429,228,004,229,873.19(0.15) Hz, where the stated uncertainties are dominated by statistical noise and gaps in the observation interval ('dead-time' uncertainty).


Absolute frequency measurement, precision metrology, primary standards, atomic clocks, optical frequency comb


Leopardi, H. , Beloy, K. , Bothwell, T. , Brewer, S. , Bromley, S. , Chen, J. , Diddams, S. , Fasano, R. , Hassan, Y. , Hume, D. , Kedar, D. , Kennedy, C. , Khader, I. , Leibrandt, D. , Ludlow, A. , McGrew, W. , Milner, W. , Nicolodi, D. , Oelker, E. , Parker, T. , Robinson, J. , Romisch, S. , Sherman, J. , Sonderhouse, L. , Swann, W. , Yao, J. , Ye, J. , Zhang, X. and Fortier, T. (2021), Measurement of the 27Al+ and 87Sr absolute optical frequencies, Metrologia, [online], (Accessed May 28, 2024)


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Created January 20, 2021, Updated March 1, 2021