双耦合Λ型三能级系统的量子相干特性

Quantum Coherence Properties in Lambda Three-Level System Driven by Two Coupling Fields

对双耦合场作用下的Λ型三能级系统的量子相干特性进行了理论研究。通过求解相应的系统密度矩阵方程,得到不同条件下的探测吸收谱,研究了探测场的吸收谱线随耦合场的频率及作用强度的变化规律。结果表明,当两个耦合场分别共振作用于相应的跃迁能级时,所得到的探测吸收谱线既有吸收又有放大,呈现为双电磁诱导吸收(EIA)峰与Mollow谱线的叠加。进一步分析给出了双EIA和Mollow谱线的位置、幅度随双耦合场拉比(Rabi)频率的变化规律,并采用缀饰态理论对这一规律做出了解释。提出通过调节共振耦合场的作用强度可以实现EIA和Mollow谱线位置的频率调谐。

Quantum coherence of a Λ-three-level scheme driven by two coupling fields is investigated.By sloving density matrix motion equations under dipole approximation and rotating wave approximation,numerical results are obtained.It is shown that the probe absorption spectrum has amplification as well as absorption when both coupling fields are resonant with corresponding resonant transitions,and it exhibits the superposition of double electromeqnetic induced absorption（EIA） and Mollow profile.The dependence of the position and intensity of the double EIA and Mollow profile on Rabi frequency of two coupling fields is investigated.The results can be accounted for dressed-state formalism.Therefore,EIA and Mollow frequency tuning can be performed by changing the intensity of the coupling fields.