The Study Of Coherent Dynamics Of Collective Radiation System

The study of the interaction of optical field with matter is currently being a hot research area in physics. Quantum coherent control has been the forefront issue in the field of quantum optics field. In the multi-atom system, collective radiation effect and spontaneously generated coherence,which have a profound impact on the spontaneous emission processes, have attracted tremendous research interests.In this thesis, we mainly investigate the quantum coherent control of coherent dynamics of collective radiation effect in the multi-atom system. We investigate the potential applications for the quantum coherent control of the X-ray superradiance. The propagation behaviors of few-cycle pulses in a dense two-level medium are also investigated by taking the collective radiation effect into account. The main innovative achievements and important results are as follows:1. The Hamiltonian of the interaction of optical field with matter in an ensemble of two-level atoms has been studied with the full quantum theory. Based on the Hamiltonian, the master equation has been derived to describe the dynamics of an ensemble of two-level atoms interacting with each other via a single-mode coherent light field, which can indicate the collective radiation processes and decay-induced coherence.2. The quantum coherent control of the X-ray superradiance with the wavelength λ = 4.03 nm in an ensemble of Λ-type helium-like carbon 4+ ions has been investigated by using the master equation. Suggests that the peak values of the X-Ray superradiance pulse intensity could be controlled by changing the Rabi frequency of driving field near ultraviolet region. Due to the constructive interionic and intraionic inference, the intensity and the splitting feature of the superradiance pulses could be controlled by the ions density and by the intensity of the driving field.3. Generalized Maxwell-Bloch equations in two-level medium has been driven. By comparing the Maxwell-Bloch equations in sparse and dense media, the effect of collective radiation effect on the propagation of ultra-short laser pulses in a dense two level medium system has been studied. The use of finite difference time domain(FDTD) solution has been investigated to solve the generalized Maxwell-Bloch equations.