Transient coherent oscillations in a closed A system under far-off resonant Raman fields were investigated theoreti- cally. It has been found that the coherent superposition of the ground states can be formed due to t...Transient coherent oscillations in a closed A system under far-off resonant Raman fields were investigated theoreti- cally. It has been found that the coherent superposition of the ground states can be formed due to the absorption even for initial maximal mixed ground states. The absorption oscillates with a period depending on the two-photon detuning when the system is initially in a transparent state and the two-photon Raman detuning is suddenly changed. The amplitude of the absorption decays with the decay rate of the ground states, which is different from the case when the lasers are applied resonantly. These transient coherent oscillations can be used to measure the relaxation rate of the ground states.展开更多
Light shift is important and inevitably affects the long-term stability of an atomic clock.In this work,considering two unbalanced branches of the spontaneous decay rate in a three-level system,we studied the frequenc...Light shift is important and inevitably affects the long-term stability of an atomic clock.In this work,considering two unbalanced branches of the spontaneous decay rate in a three-level system,we studied the frequency shifts of electromagnetically induced transparency(EIT)and coherent population trapping(CPT)clocks operating under the pulse sequence regime by numerically solving the Liouville density matrix equations.The results show that the frequency shifts are larger when the two branches of spontaneous emission rate are not equal compared to the equal case.In addition,in EIT-Ramsey,the effect of the unbalanced branches of the spontaneous decay rate and relaxations of low-energy states on the frequency shift is greater than that of Rabi frequency.In CPT-Ramsey,the relaxations of low-energy states play a dominant role in frequency shift.展开更多
基金Project supported by the Knowledge Innovation Program of the Chinese Academy of Sciences and the National Basic Research Program of China
文摘Transient coherent oscillations in a closed A system under far-off resonant Raman fields were investigated theoreti- cally. It has been found that the coherent superposition of the ground states can be formed due to the absorption even for initial maximal mixed ground states. The absorption oscillates with a period depending on the two-photon detuning when the system is initially in a transparent state and the two-photon Raman detuning is suddenly changed. The amplitude of the absorption decays with the decay rate of the ground states, which is different from the case when the lasers are applied resonantly. These transient coherent oscillations can be used to measure the relaxation rate of the ground states.
基金Project supported by the State Key Laboratory of Low Dimensional Quantum Physics Research Program,Tsinghua University(Grant No.KF201707).
文摘Light shift is important and inevitably affects the long-term stability of an atomic clock.In this work,considering two unbalanced branches of the spontaneous decay rate in a three-level system,we studied the frequency shifts of electromagnetically induced transparency(EIT)and coherent population trapping(CPT)clocks operating under the pulse sequence regime by numerically solving the Liouville density matrix equations.The results show that the frequency shifts are larger when the two branches of spontaneous emission rate are not equal compared to the equal case.In addition,in EIT-Ramsey,the effect of the unbalanced branches of the spontaneous decay rate and relaxations of low-energy states on the frequency shift is greater than that of Rabi frequency.In CPT-Ramsey,the relaxations of low-energy states play a dominant role in frequency shift.
