Transient processes under dynamic excitation of a coherent population trapping resonance

Abstract

It is shown for the first time that under dynamic excitation of a coherent population trapping resonance in Rb vapours at different bichromatic pump modulation frequencies from a few tens of hertz and higher, the resonance is dramatically deformed as a result of emerging intensity oscillations of radiation transmitted through an Rb vapour cell. A significant change in the shape of the resonance under its dynamic excitation is confirmed experimentally and theoretically. A possible impact of the identified changes in the shape of the coherent population trapping resonance on the stability of an atomic clock is qualitatively discussed.

Feedback-controlled and digitally processed coherent population trapping resonance conversion in87Rb vapour to high-contrast resonant peak

“…At high CPT resonance scanning frequency, the resonant peak contrast obtained with the back-coupling active was similarly improved, but the enhancement factor in this case was considerably lower, not exceeding 25. This is probably due to a considerable deformation of dynamically excited CPT resonant line profile with simultaneous degradation of the SNR [25]. The corresponding resonances without (blue curve) and with (red curve) feedback at scanning frequency of 2kHz are given in figure 5.…”

Relationship between coherent population trapping oscillation and Raman detuning

“…不同的频率调制方式会导致拉曼失谐的变化方式 不同, 进而引起不同的CPT瞬态振荡过程. 然而, 目前已有的研究大多聚焦于采用方波、正弦波对微 波频率进行调制, 探究相干双色激光频差发生阶跃 变化和非均匀变化对CPT瞬态振荡的影响 [9][10][11][12] , 针对相干双色激光频差均匀变化方面的研究相对 较少. 此外, 已有研究表明, 扫描速率过快会增强 NMOR瞬态过程 [14] , 但针对扫描速率对CPT瞬 态过程影响的研究仍是空白.…”

“…演化方程组可以使用刘维尔(Liouville)方程来推 导 [12] . 已有研究广泛采用假设两束激光拉比频率 相等(均为Ω), 且两束激光与能级之间的单光子失 谐满足Δ 1 = Δ 2 的方式, 实现简化计算的目的 [10,11] .…”

Fluorescence of rubidium vapor in a transient interaction regime

“…To the best of our knowledge, there are just a few works on atomic spectroscopy with cw excitation radiation, where transient resonant interaction processes were studied. Particularly, theoretical and experimental investigations of processes under dynamic excitation of atomic media with modulated cw laser radiation were done for nonlinear magneto-optical processes [1], saturation spectroscopy [2], four-wave mixing [3], coherent population trapping [4,5]. Analytical solutions of temporal evolution of populations in optically-pumped atoms were obtained in [6].…”