摘要
提出开放的四能级双驱动场无反转激光系统的理论模型,由电偶极和旋转波近似得到其密度矩阵方程,讨论无反转激光产生的物理机制,利用数值计算结果分析探测场和驱动场失谐对系统无反转激光增益和粒子数差的影响.
A model for an open four-level atomic system driven by two fields is presented. Density matrix equations of motion are obtained by electric dipole and rotating wave approximations. Physical mechanism of lasing without inversion （LWI） is discussed. Effects of detuning on gain without inversion and population difference are studied. Dispersion equals to zero as two driving and probe fields are resonant. As one driving field （probe field ） is resonant, the gain and the population difference versus detuning of driving field （probe field）show even symmetry, and the dispersion shows central symmetry. As two or three of driving and probe fields are off-resonance, the symmetries disappear. LWI gain is obtained when the dispersion equals to zero. When beth driving and probe fields are off-resonance, the gain, the dispersion and the population difference change greatly. High dispersion without absorption is obtained by adjusting suitable parameters of the system.
出处
《计算物理》
CSCD
北大核心
2008年第5期607-611,共5页
Chinese Journal of Computational Physics
基金
济南大学科技基金(Y0413)资助项目
