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

Research output: Contribution to journalArticlepeer-review

33 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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