By using numerical calculation and graphs,the relations between steadystate solutions of moving three-level ladder-type atom in bichromatic traveling fields and Dopper-shift are discussed here.It is found that doppler-shift can influence the resonant position and Dopper-shift is more obvious if Rabi frequency is larger.
By analyzing the influence of the motion of the atoms on the steady-state populations of the atomic levels,we found that the Doppler frequency shift in the double-photon resonance occurs near to the zero double-photon detuning and the Doppler frequency shift in the single-photon resonauce near to the zero single-photon detuning.The double-photon resonance near to zero double-photon detuning does not make the Doppler frequency shift occured when atoms are driven by two counter propagating but same frequency laser beams.
Radiation pressure and laser cooling of a moving three-level ladder-type atom in bichromatic travelling fields are considered. The dependence of the force on parameters such as detunings, Rabi frequencies and spontaneous decay rates is calculated numerically and shown graphically and analytical expressions for the force are obtained for some special parameter values. It is shown that the radiation pressure shows Doppler-shifted resonance peaks resulting respectively from one-photon and two-photon transitions. Using the present scheme, Doppler cooling of sodium exploiting the 3 2 S 1/2 –3 2 P 3/2 –3 2 D 5/2 cascade transitions is investigated. It is found that temperatures lower than the Doppler limit can be achieved.
This paper mainly deals with the steady-state population of a moving ladder-type three-level atom,driven by a superposition of a monochromatic laser wave with a broad-band squeezed vacuum,From the Hamiltonian of the atomic system,making use of Born-Markoff approximation,we derive the master equation for the system and the atomic Bloch equations and obtain the steady-state solutions of the optical Bloch equations using numerical calculation.Then we discuss the dependence of the attained population σ_(ii) on parameters such as detuning Δ,Rabi frequencies e_1e_2,phase ,squeezing photon number N and spontaneous decay ratesγ_1 γ_2 etc in different cases by using graphical method.
The dipole force's steady solution of a ladder-type three-level atom of nearly equispaced energy level driven by a standing wave is derived from the atomic master equation.The variance of dipole force and the population of the energy level with the detunings,the space and the amplitude are shown by numerical calculation.The results show that the dipole force is proportional to the gradient of amplitude of the standing wave and the coherences between the atomic internal states plays a modulating role on the force,which is the most remarkable near the two-photon resonance point.Besides the levels tend to reach a equal-population and the dipole force tend to be zero as the amplitude of the electric field becomes bigger.
A theoretical study is made of the dissipative force and Doppler cooling of a ladder-type three-level atom coupled to a travelling coherent light beam. The dependence of the force on parameters such as detunings, Rabi frequencies, spontaneous decay and coherence transfer rates is calculated numerically and shown graphically. Analytical expressions for the force are obtained for special parameter values. It is shown that for suitable choices of parameter values, it is possible to cool three-level atoms to temperatures down below the Doppler limit.