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In the last ten years extraordinary results in time and frequency metrology have been demonstrated. Frequency stabilization techniques for continuous wave lasers and femto-second optical frequency combs have enabled a rapid development of frequency standards based on optical transitions in ultra-cold neutral atoms and trapped ions. As a result, today's best performing atomic clocks tick at an optical rate and allow scientists to perform high resolution measurements with a precision approaching a few parts in 1018. This paper reviews the state of the art in optical clock research and addresses the implementation of optical clocks in a possible future redefinition of the SI second as well as in tests of fundamental physics.
Citation
Rivista Del Nuovo Cimento
Volume
36
Issue
12
Pub Type
Journals
Keywords
Atomic Frequency Standards, Femtosecond Frequency Combs, High Resolution Laser Spectroscopy, Optical Atomic Clocks