Atomic clock based on transient coherent population trapping

Abstract

We proposed a scheme to implement coherent population trapping (CPT) atomic clock based on the transient CPT phenomenon. We proved that the transient transmitted laser power in a typical Λ system near CPT resonance features as a damping oscillation. Also, the oscillating frequency is exactly equal to the frequency detuning from the atomic hyperfine splitting. Therefore, we can directly measure the frequency detuning and then compensated to the output frequency of microwave oscillator to get the standard frequency. By this method, we can further simplify the structure of CPT atomic clock, and make it easier to be digitized and miniaturized.

A magnetometer based on coherent population beating

“…As is shown in Fig.1, CPB occurs in a typical threelevel system, when the frequency difference (ω 21 ) of the two pump laser fields is equal to the ground states splitting (Δ 21 ), it's a typical coherent trapping phenomenon. However, when ω 21 has a detuning from Δ 21 , a damping oscillation will be observed from the photodiode, and the oscillation frequency is equal to the detuning |Δ 21 -ω 21 | [3,4].…”

An atomic frequency micrometer based on the coherent population beating phenomenon

“…The CPB phenomenon has been observed and studied by various groups (under different titles) and has been theoretically and experimentally approved [1,2,8] CPB occurs in a typical three level Λ system (Fig.1). When the frequency difference of the two pump laser fields ω21=ω1−ω2 equals the ground state hyperfine splitting frequency Δ21, all the electrons will be trapped within the two ground states.…”

“…It is conceivable notion that if we directly beat the measured frequency with the atomic transition frequency, we could omit the intermediate process with the atomic clock, and achieve the frequency precision measurement with the atomic transition itself being the frequency standard, which would be much more accurate and reliable. In this paper we will demonstrate how the coherent population beating [1,2] (CPB) phenomenon and the rapid development of digital signal (DSP) processing technology helped us to achieve this goal.…”

“…olution of ρ 33 can (1) e derivation have constant, is the s. Δ=| ∆ | is ncy (we assumed e. According the ion of ρ 33 . The an lineshape with n be simplified to ne width 9 .…”

An atomic clock based on the transient coherent population trapping detuning oscillation phenomenon

“…Figure.1 shows a typical Ʌ system, such as D1 line of 85 Rb [6]- [7], with the two hyperfine ground-states |1> and |2>, as well as the excited state |3>. Γ is the decay rate from the excited state to the two ground levels considering the effects of both spontaneous emissions and collisions with buffer gas atoms [8]. The population difference and coherence in the two ground states tend to zero at the rates γ 1 and γ 2 , respectively [9]-[10].…”