The last four years have seen a revolution in the art and practice of optical frequency measurement. Indeed the gearbox represented by the spectrally-broadened fs laser's comb has sufficiently low noise that we in the optics community have abruptly found ourselves in the tough real world well known to our rf standards colleagues who perpetually work toward more coherent interrogation oscillators. As suggested earlier by Dehmelt, a trapped, laser-cooled single-ion con form an excellent basis for a fundamental new frequency standard system. Still, laser-cooled cold gas ensembles typically offer higher S/N and so better short-term stability, but at some cost in possible shifts of the resonance spectrum. In the effort to obtain excellent stability and reproducibility from simpler (gas cell) systems, emphasis is on getting smaller shifts in the process of observing the atomic resonance. Time-domain synchronization achieved by frequency-domain methods, brings a whole new order of experimental precision.
Optical Frequency Standards and Their Measurement
Book Chapter ,
laser frequency standards, optical frequency measurement, time domain synchronization
and Ye, J.
Optical Frequency Standards and Their Measurement, Book Chapter ,
(Accessed June 2, 2023)