Optical Atomic Clocks for Ground and Space Applications

Markus P. Plattner, K. Kemmerle, Timo Stuffler

Eric A. Burt

Patrick Robert Gill, Helen S. Margolis, Anne Curtis +4 more

Richard A. Dunlap

The final chapter of this book considers some applications of ultracold atoms in addition to the study of Bose–Einstein condensates. These applications focus largely on the use of ultracold atoms for the purpose of constructing a highly accurate atomic clock. These clocks include atomic fountain clocks, which are presently used for the definition of the second. These clocks operate at microwave frequencies by observing the transitions between hyperfine split atomic ground states. More recent developments in atomic clocks utilize optical transitions between the ground state and an excited atomic state and typically utilize atoms trapped in an optical lattice.

David R. Gozzard, L. A. Howard, Benjamin P. Dix-Matthews +3 more

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 6.1×10^{-21} 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.

Gretchen R. Phelps, N. Lemke, Chris Erickson +1 more

We report on the development of an atomic clock for both ground and space applications, based upon the two-photon transition in Rb. Off-the-shelf components allow for a simple architecture that supports 7 × 10 − 13 / τ at 1 second.