场的相干和能级的近简并对共振两能级系统占据几率的影响

讨论了共振三色及多色场的相干作用,它可能导致比单、双色场更大的占据几率翻转。应用密度矩阵计算了上能级分裂为两个近简并能级时各种参数值的稳态解,发现在适当条件下激发态对基态占据几率翻转。

Effect of interference between polychromatic fields and near-degeneracy of levels on population of two level systems

In this paper the pumping of a two level system by nearly resonant polychromatic field is discussed. It is pointed out that owing to the interference between field, one can obtain greater population inversion in the case of pumping by a monochromatic or dichromatic field. For the case in which the upper level splits into two nearby ones, the method of density matrix is used to calculate the steady-state solution for various parametric values. It is found that population inversion can be obtained at definite conditions.