This dissertation could be divided into three parts. First part is devoted to represent the fundamental role of quantum control in the generation of quantum technology. The grounds and materials of quantum control is broadly surveyed including some topics such as modeling, controllability, quantum networks, quantum filtering, open-loop and close-loop control. In the second part, a basic question in control engineering is answered which is how a system responds to the different inputs? This question is addressed by estimating the system state using quantum filtering for a two-level quantum system driven by various inputs including vacuum state, multimode single-photon and superposition of coherent states. The purity of state is also considered and its dynamic is derived as another parameter of system behavior.Pure states representquantum states of maximal information andthey are desired in many applications. Finally, an algorithm is presented tocontrol a quantum system based on feedback. The controller design is based on derivation of closed-loop stochastic Schr?dinger equation and satisfying a stabilization condition which is defined. The proposed method is applied to steers the state of two-level quantum system from any initial state into any desired state. The simulation results show the validity of the proposed method. Keywords: quantum feedback control, behaviour of quantum system, purity of state of quantum system, multi-mode single photon, superposition of coherent states, stochastic Schr?dinger equation
