An accurate measuring method for the transient oscillation frequency of detuned coherent population trapping atomic clock

We proposes a method for measuring the transient oscillation frequency observed when Coherent Population Trapping is excited by means of optical pumping radiation fields whose frequency difference is detuned slightly from the ground state hyperfine frequency of the atom used. Using narrow-band simulation filter and phase matching techniques this measuring method can provides a measurement precision of about 0.5Hz. Based on this reading accuracy the DCPT atomic clocks frequency instability can be better than 5e-11 (t=100s) and tend to more stable at longer integration time. According to our experimental results, we demonstrate that a DCPT atomic frequency standard could give good short and long term frequency stability.