In the last ten years extraordinary results in time and frequency metrology have been demonstrated. Frequency stabilization techniques for continous 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
Pub Type: Journals
Atomic Frequency Standards, Femtosecond Frequency Combs, High Resolution Laser Spectroscopy, Optical Atomic Clocks