本报告将简要介绍相干原子动力学特性有关的理论工作。第一部分介绍超冷里德堡原子系综中电磁诱导透明（EIT）的相干瞬态光学响应特性。研究表明，在里德堡原子系综里，由于存在偶极阻塞效应，EIT 吸收谱达到稳态所需要的响应时间要比无里德堡相互作用的情况短。我们分别用两原子和多原子半经典模型，证实了里德堡原子中EIT的快速响应特性。第二部分介绍基于超冷原子EIT的四波混频（FWM）量子噪声抑制。初步研究表明，当选择相位调制的多模压缩真空态作为入射量子态，可以有效地抑制四波混频系统中增益模式的激发，从而抑制量子噪声的放大。

We present here a brief review of our theoretical works on the dynamics of light-atom interaction of atomic ensemble during my Ph. D. In the first part, we investigate the coherent transient optical response property of electromagnetically induced transparency (EIT) in an ensemble of cold Rydberg atoms. We show that under suitable experimental parameters, the response speed of the Rydberg-EIT can be much faster than that of the conventional EIT without the Rydberg interaction, due to the Rydberg dipole blockade effect. Two different semi-classical approaches (i.e., two-atom and many-atom models) are considered, indicating the fast-responding property of Rydberg-EIT. In second part, we give a preliminary study on the suppression of the quantum noise in the EIT-based four-wave-mixing (FWM) atomic medium. We show that the excitation of the gain mode can be effectively suppressed by inputting the entangled probe and Stokes fields of the phase-modulated multimode squeezing vacuum state. Consequently, the optical gain on the two fields and the quantum vacuum noise can be largely minimized.