Study On Bistable Characteristics Of Asymmetric Quantum Wells Induced By Resonant Tunneling

Nonlinear optical characteristic is the popular researching direction of the laser physics and quantum optics and other subjects in recent years, and is one of the important international studying problems for the optics as well. What is more, the studying of the nonlinear characteristic can promote the development of quantum optics and other disciplines. To the nonlinear optics interactions between the optical field and the coherent medium, its ultimate aim is to deeply reveal the physical nature in the interaction of the field and the medium. In recent years, many scholars have done a lot of researching work by using the methods of the atomic or quantum coherence, such as electromagnetically induced transparency, the tunable Fano interference, the coherence of the spontaneous radiations, etc., and they successively acquired a series of important achievement. Optical bistable characteristics of the medium have the widespread applications in the quantum optics and nonlinear optics. With the deepening of the research on the optical bistable phenomenon, the various studying in the traditional atomic system have been fairly deep. But with the development of the high-tech nano technology changing constantly, the research of optics bistability gradually spreads to the field of the semiconductor nanometer microstructure. Nano semiconductor quantum wells structures for the study of optical bistability have more advantages to be relative to the atomic systems, for example, the flexibility of the structure design, which thus have caused many researchers to investigate the quantum optics and nonlinear optics with quantum wells structures and explore those problems, it not only helps us to understand quantum coherent nonlinear effects in semiconductor structures but also provides the theoretical guiding basis with the coherent effect for the study of the optical bistable devices in the semiconductor microstructure.We mainly put forward the scheme of the optical bistable characteristic under the interactions of the optical field and the asymmetric semiconductor quantum wells system in this thesis. Based on the tunneling coupling effect, we have made a relatively thorough theoretical study, the details mainly include the followings:1. Firstly, we mainly expound the present situation and the research background and research history of it. Based on the interference of the material and optical field in the article, we demonstrate the studied general dynamic situation of the optical bistable properties, and put forward the research question of this paper and the important solutions.2. Secondly, we expound the foundational theory research of this letter, including the three basic pictures during the quantum systems in this paper, the semiclassical theories of the interaction between optical field and the atomic medium, the interacting theories of the optical field and a two-level atomic system. And it introduces the propagation theory of the optical field in the atomic medium and the density matrix method.3. Thirdly, based on the tunneling coupling resonance, we have discussed the optical bistable characteristics in a unidirectional ring cavity under the interactions of asymmetrical quantum wells system and the laser fields. The discussion which consists of the absorptive and dispersive types is also an involving mixed bistable system. In the two-photon resonant case, the study shows that the tunneling coupling effect in the asymmetric quantum wells structure plays an important role in the optical bistable phenomenon. At the same time, the thorough numerical analysis also shows that the coupling intensity or the frequency detuning of the driving field have an important role on the optical bistable phenomena with the appropriate parameters under the condition of the tunneling coupling interference. It should be pointed out that the bistable threshold is controlled by the electronic cooperative parameter of the studying sample.4. Finally, we summarize the research findings of our discussion. Meanwhile, we also studied the potential prospects of the relevant research and practical application in the future.In conclusion, the discussion of the optical bistability not only helps us to understand and master the relevant quantum interference properties of the semiconductor quantum wells materials but also brings many advantages for the study of the nonlinear optical quantum coherence characteristics of optical bistable phenomenon in the semiconductor quantum wells materials for the article, then it can open the research of the optical bistable vision in the new materials. Meanwhile, to a certain extent, the paper will promote the further development of the optical bistable studying systems, including the theories and experiments. It can enhance the potential applications of the all-optical communications and the optical quantum information processing with the pure optical bistable system, and also provides a necessary theoretical guidance. At the same time, those investigations will form the great significance in the all-optical switch, optical information storage and extraction of components, nonlinear spectroscopy, quantum information science, many other new and high technology researching projects and the development of the overlapping discipline in the future.