Frequency Measurements of Superradiance from the Strontium Clock Transition

Matthew A. Norcia*, Julia R.K. Cline, Juan A. Muniz, John M. Robinson, Ross B. Hutson, Akihisa Goban, G. Edward Marti, Jun Ye, James K. Thompson

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

60 Citations (Scopus)


We present the first characterization of the spectral properties of superradiant light emitted from the ultranarrow, 1-mHz-linewidth optical clock transition in an ensemble of cold Sr87 atoms. Such a light source has been proposed as a next-generation active atomic frequency reference, with the potential to enable high-precision optical frequency references to be used outside laboratory environments. By comparing the frequency of our superradiant source to that of a state-of-the-art cavity-stabilized laser and optical lattice clock, we observe a fractional Allan deviation of 6.7(1)×10-16 at 1 s of averaging, establish absolute accuracy at the 2-Hz (4×10-15 fractional frequency) level, and demonstrate insensitivity to key environmental perturbations.

Original languageEnglish
Article number021036
JournalPhysical Review X
Issue number2
Publication statusPublished - 2018 May 9
Externally publishedYes

ASJC Scopus subject areas

  • Physics and Astronomy(all)


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