Ultrastable Free-Space Laser Links for a Global Network of Optical Atomic Clocks

D. R. Gozzard, L. A. Howard, B. P. Dix-Matthews, S. F. E. Karpathakis, C. T. Gravestock, S. W. Schediwy

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33 Citations (Scopus)
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A global network of optical atomic clocks will enable unprecedented measurement precision in fields including tests of fundamental physics, dark matter searches, geodesy, and navigation. Free-space laser links through the turbulent atmosphere are needed to fully exploit this global network, by enabling comparisons to airborne and spaceborne clocks. We demonstrate frequency transfer over a 2.4 km atmospheric link with turbulence comparable to that of a ground-to-space link, achieving a fractional frequency stability of 6.1×1021 in 300 s of integration time. We also show that clock comparison between ground and low Earth orbit will be limited by the stability of the clocks themselves after only a few seconds of integration. This significantly advances the technologies needed to realize a global timescale network of optical atomic clocks.
Original languageEnglish
Article number020801
JournalPhysical Review Letters
Issue number2
Publication statusPublished - 14 Jan 2022


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