Controlling Optical Properties By The Coupling Effect In Semiconductor Quantum Materials

Since entering the information age, the requests of information processing become higher and higher with the growing amount of information. However, the traditional information processing methods have gradually approached the physical limitation. It is the inevitable trend in information research to search for new information processing methods and information medium. With the significant advantage such as large electric dipole moments of the transitions, high nonlinear optical coefficients, small size as well as easily operating and integrating, the semiconductor quantum construction material is considered as the preferred new approach of information medium. Meanwhile, the significant nonlinear optical effects can be obtained, and the strong resonance absorption of medium can be inhibited in the system. As far as we know, the most resent reseach are focused on the single quantum dot and well and do not considere the coupling effect in the semiconductor functional quantum structure, such as tunneling coupling in the semiconductor quantum dotand coherent longitude-optical phonons coupling in the semiconductor quantum well. This handling method limites us to understand the physics mechanism, although it makes the theoretical calculation simplify. Consequently, it is of interest to study the effect of tunneling coupling and longitude-optical phonons relaxation cross-coupling on the nonlinear optical phenomenon in semiconductor nanostructures. It is not only for comprehending of the nature of quantum coherence and interference effects, also for the possible realization of optical devices based on such coherent and interference properties. The major work can be summarized as the follows:1) The linear optical properties in a four level loop configuration GaAs/AlGaAs semiconductor quantum dot are analytically studied with the phonon-assisted transition (PAT). It is shown that the change among a single electromagnetically induced transparency (EIT) window, a double EIT window and amplify of the probe field in the absorption curves can be controlled by varying strength of PAT. Meanwhile, double switching from the anomalous dispersion regime to the normal dispersion regime can likely be achieved by increasing the Rabi energy of the external optical control field. Furthermore, we demonstrate that the group velocity of probe field can be practical regulated by varying the PAT and the intensity of the optical control field.2) Considering the coupling effect between interdot tunneling coupling and external optical control field, we study the propagation property of the weak probe field. The results show that the double tunneling induced transparency (TIT) windows are appeared in the absorption curve of probe field because of the formation of dynamic Stark splitting and quantum destructive interference effect from the two upper levels. Interestingly, the width of the TIT window becomes wider with the increasing intensity of the optical control field. We also find that the Kerr nonlinear effect of the probe field can be modulated effectively through coherent control both the control field and the interdot tunneling coupling in this system. Meanwhile, we demonstrate that the formation of dark or bright solitons can be practical regulated by varying the intensity of the optical control field.3) Four-wave mixing (FWM) processes based on atomic coherence and quantum interference have been the focus in the optics and its relative recent studies. This is because of its potentially wide range of applications in high-efficiency generation of coherent radiation, quantum nonlinear optics, quantum information science, and so on. The previous investigations on the field of FWM are focusing on the passive optical medium and cold atomic medium. For low efficiency and low operating temperature in these medium, it can not be conveniently used in devices with good scalability. So, we theoretically study the controllable high efficiency FWM in a four-level coupled quantum wells with the interband transition and the cross-coupling of coherent longitude-optical phonons relaxation under Raman excitation. It is shown that the probe field propagate with an extremely slow group velocity and the conversion efficiency of the FWM increasing both the amplitude and the conversion efficiency of the FWM field enhance greatly The results can be interpreted by the effect of electromagnetically induced transparency and the indirect transition.