The dispersive properties of an excited-doublet four-level atomic system

We have investigated the dispersive properties of excited-doublet four-level atoms interacting with a weak probe field and an intense coupling laser field. We have derived an analytical expression of the dispersion relation for a general excited-doublet four-level atomic system subject to a one-photon detuning. The numerical results demonstrate that for a typical rubidium D1 line configuration, due to the unequal dipole moments for the transitions of each ground state to double excited states, generally there exists no exact dark state in the system. Close to the two-photon resonance, the probe light can be absorbed or gained and propagate in the so-called superluminal form. This system may be used as an optical switch.

Transient responses of transparency in a far-off resonant atomic system

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.

Analytical solution of microwave transition spectral lines for ^(87)Rb atoms in a Hanle configuration

This paper theoretically investigates the microwave transition spectrum of STRb atomic D1 line with specially prepared atomic state in a Hanle configuration. The approximate analytical results have shown that the 0-0 transition spectral line has the highest contrast and can be applied to microwave frequency standards.

Gain and Absorption of a Probe Light in an Open Tripod Atomic System

We theoretically investigate an open four-level atomic system interacting with control,probe and microwave fields.When there is no repumping light and a microwave field is applied,the probe light can be absorbed or amplified,which has different features than those of a system whose populations are pumped into only one ground state.In this system the microwave field and the population distributions of the ground states can be used as switches to control the propagation of the probe light.

Experimental Demonstration of Electromagnetic Induced Transparency and Dispersion Effects in Cs Atom Vapour

The effects of the electromagnetically induced transparency and dispersion of a A-type three-level atomic system are experimentally measured with a vapour cell of Cs atoms. The steep dispersion at low absorption is observed. Thus a small group velocity for the probe beam is inferred from the measured dispersion curve.

Ultranarrow absorptive spectral line induced by microwave field

This paper investigates the absorptive spectral lines of four-level atomic system driven by a coupling, probe and microwave fields. Due to the perturbation of the microwave field, the original electromagnetically induced transparency is changed to electromagnetically induced absorption and the absorptive spectral line can be very narrow. This ultranarrow spectral line has potential applications to the microwave atomic frequency standard and the measurement of very weak magnetic field.

Enhanced Kerr Nonlinearities Caused by Cross Talk Between Optical and Microwave Transitions

We investigate the enhanced Kerr nonlinearities in four-level atomic vapors driven by a coupling,probe andmicrowave fields.Under the optical one-photon and two-photon resonant conditions,the linear and nonlinear responsesof the weak probe field can be modified by the cross talk among optical and microwave transitions.The enhanced Kerrnonlinearity can form bright optical solitons of the probe field.

Light-shift induced by two unbalanced spontaneous decay rates in EIT(CPT)spectroscopies under Ramsey pulse excitation

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.