Optical atomic clocks

  title={Optical atomic clocks},
  author={Nicola Poli and Christopher W. Oates and Patrick Gill and Guglielmo Maria Tino},
  journal={Rivista Del Nuovo Cimento},
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… 
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