Nonlinear Optical Properties In Semiconductor Quantum Dots Electromagnetically Induce Transparency Medium

In recent years, the study on electromagnetically induced transparency effect based on quantum coherence has become one of the hot issues in the field of the nonlinear optics. The main reason is that by making use of the electromagnetically induced transparency effect, the significant nonlinear optical effects can be obtained, and the strong resonance absorption of medium can be inhibited. Therefore, it provides a possible way to resolve the irreconcilable contradictions between the strongly nonlinear response and the loss of weak absorption. As far as we know, the most recent investigations field on the electromagnetically induced transparency medium is mainly concentrated in ultracold atoms. However, it is difficult to be widely used in the design of the device miniaturization due to the defects of low-temperature and thin in the medium of ultracold atoms. Fortunately, the semiconductor quantum dots, which have the discrete energy level structure being similar to ultracold atoms, larger electric dipole moment, longer decoherence time, the controllable coherent evolution and the advantages of the ease of integration, can produce electromagnetically induced transparency effect. Therefore, it becomes one of the new ideal information carrier medium. Up to now, the investigation of nonlinear optical properties in the semiconductor quantum dots electromagnetically induced transparency media is still in the initial exploration stage. Based on this, our main study work is focused on nonlinear optical properties of temporal vector optical solitons and the nonlinear faraday deflection in semiconductor quantum dot system with the electromagnetically induced transparency effect. The structure of the thesis is in the following.In the first chapter, some concept, classification and the research situation at home and abroad of semiconductor quantum dot system are introduced at first. Subsequently, the basic theory and research method about our study are introduced briefly. The main research contents of our thesis are shown at last.In chapter 2, collision characteristics of temporal vector optical solitons in single semiconductor quantum dot media with the electromagnetically induced transparency is analytically investigated. We first propose a theory model of the four-level type single semiconductor quantum dot system with the electromagnetically induced transparency, which is composed of a semiconductor quantum dot system interacting with a weak, linear-polarized probe field with two orthogonally polarized components under the applied longitudinal magnetic field and two strong coupling control fields. Then, based on the above theory model, the stability and collision dynamical characteristics of two coupled temporal vector optical solitons in the semiconductor quantum dot with the electromagnetically induced transparency are analytically investigated by using the multiple-scale method. The results show that it is able to form two coupled temporal vector optical solitons, which is evoluted by two orthogonally polarized components of the probe field, and the two coupled temporal vector optical solitons can propagate steadily with super slow group velocity in the semiconductor quantum dot media with the electromagnetically induced transparency due to the balance between the dispersion effect and the nonlinear effect. Because the two coupled temporal vector optical solitons can propagate steadily, the collision characteristics of the two coupled temporal vector optical solitons may be further studied. Subsequently, by numerical simulating the collision between two temporal vector optical solitons, it is shown that their collision properties are correlated with their initial phase shift values. Especially, when the initial phase difference is ?2, they will be separated from each other after their collision and there will is energy transfer between two temporal vector optical solitons. While the two components of temporal vector optical solitons are in phase or out of phase, the collisions between them are almost elastic and there is no energy transfer about the two components of temporal vector optical solitons at the same time. The collision behavior of two temporal vector optical solitons without energy transfer in single semiconductor quantum dot media is beneficial to the signal propagation of optical soliton communication.As a matter of fact, some single semiconductor quantum dot can form quantum dot molecule, which can be coupled by interdot tunneling coupling. Consequently, the impact of the interdot tunneling coupling strength must be considered in nonlinear optical properties of semiconductor quantum dot molecule. In chapter 3, we theoretical study the Faraday rotation in three semiconductor quantum dots medium with the electromagnetically induced transparency. Considering a weak, linearpolarized probe field with two orthogonally polarized components under the applied longitudinal magnetic field, then adjusting the coupling effect of interdot tunneling coupling properly, the Faraday rotation in electromagnetically induce transparency medium of five-level M-type semiconductor three quantum dots is analytically investigated. It is found that the width of tunneling induced transparency window of the three semiconductor quantum dots can be effectively controlled and it is possible to realize the regulating effect of switching in which switching from the anomalous dispersion regime to the normal dispersion regime occurs when we adjust the interdot tunneling coupling strength appropriately in the linear case. From the nonlinear case, the results show that a large nonlinear Faraday rotation angle can be obtained due to the quantum interference effect which is induced by the interdot tunneling coupling with a very low absorption of the weak, linear-polarized probe field. Furthermore, we find that for the same magnetic field, the direction of the nonlinear Faraday rotation is opposite in comparison to that of the linear Faraday rotation, and its rotation angle becomes bigger than that of linear Faraday rotation. These results mean that Faraday rotation of the three semiconductor quantum dots with the electromagnetically induced transparency can be more effectively controlled by the nonlinear effect.In the finally chapter, we make a brief summary of our work, and look forward to a further investigation on the related phenomena of nonlinear optics in the frontier area of semiconductor quantum dot.