Patent ID: 7501906

Claim:
A method for generating an atomic clock signal with coherent population trapping from a first and a second phase-coherent laser wave, each substantially in resonance with an optical transition of the atoms of an interactive medium, the coherent superimposition of the atomic states corresponding to the coherent population trapping of atoms producing a response signal having a resonance-extremal amplitude and representing the atomic clock signal corresponding to the variation in amplitude of the signal detected as a function of the value of the difference in frequency of the first and the second phase-coherent laser wave, wherein said method consists at least in modulating in synchronization by successive pulses the intensity of the first and the second laser wave, by a shape factor determined between a high level and a low level of intensity, the interaction between the first or the second laser wave respectively and the interactive medium being substantially limited to the duration of each successive pulse corresponding to a high level of intensity, said response signal produced during a current pulse depending on the atomic state produced during at least one pulse preceding this current pulse and on the development of this atomic state for the duration of a low level of intensity separating said pulses; and detecting and superimposing by linear combination said response signal produced during said current pulse and at least one pulse preceding this current pulse to produce a resultant compensated atomic clock signal, the spectral width of which is minimized.