Feature
Optical Lattice Clocks
A new breed of atomic clock—the “ticking” of which comes from transitions in millions of cooled atoms, trapped in optical standing waves created by tightly focused lasers—is pushing scientific timekeeping to previously unknown frontiers of precision.
Illustration by Phil Saunders/spacechannel.org
Time, though philosophically hard to grasp, can be measured far more precisely than any other physical quantity—a characteristic that has driven both new technologies and the development of basic science. Since the mid-20th-century, atomic clocks, harnessing the well-defined oscillation of electrons bound to an atom, have emerged as the gold standard for precision measurement of time and its inverse, frequency. Yet, notwithstanding dramatic improvements in atomic clocks, today’s best workhorse models—based on transitions in the microwave domain for rubidium and cesium atoms—are running up against fundamental limits to accuracy, at around one part in 1016. And that raises the question: Where will the next milestones in precision timekeeping come from?
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