Studies On The Second-harmonic Generation And Third-harmonic Generation Of The Cubic Quantum Dots And Cylindrical Quantum Dots

Since the realization of the laser, the nonlinear optics, as a new brand subject, hasbeen made extensive application in photoelectronics, biological medicine, quantum com-putation and information. Especially in the low-dimensional semiconductor microstruc-ture materials, such as quantum-well, quantum wires and quantum dots etc, they havedistinctly di?erent optical properties comparing with the bulk materials. Due to the de-cline of the dimension and the size of the low-dimensional semiconductor microstructurematerials, quantum size e?ect will be more and more obviously. Along with the develop-ment of material processing technology, for example, development of the molecular beamdenotation technology, metal organic compound chemical vapor deposition technologyand electronic lithography technology, which made it possible to produce the nanometersemiconductor devices.These devices have some incomparable advantages over bulk materials, for example,they have ultrahigh speed, high level of integration, high e?cient but low power consump-tion, low threshold current density, etc.Electronic in the nano semiconductor quantum dots will be confined in the threedirection, which has more obviously the nonlinear optical properties. So the nonlinearoptical properties of low-dimensional semiconductor quantum dots has been a hot topicin the research fields.The first chapter is introduction. First, we mainly introduces the research fields anddevelopment process of the nonlinear optics, application fields of the low dimensionalsemiconductor quantum dots, the research value of the second harmonic generation andthird harmonic generation. secondly, we mainly introduces the main contents, and thelast part we mainly introduced the theory research methods used.In the second chapter, the second-harmonic generation(SHG) for cubical quantumdots with applied electric field is theoretically investigated. In the e?ective mass approx-imation, we lay out the expression of the wave function and the energy levels of thissystem. The analytical expression of the second-harmonic generation coe?cient is ob-tained by using the compact density-matrix approach and the iterative method. We canfind that the applied electric field and the size of the quantum dots both can change themagnitude of the second harmonic generation.In the third chapter, the third-harmonic generation(SHG) for cylindrical quantumdots with applied electric field is theoretically investigated. In the e?ective mass approx- imation, we lay out the expression of the wave function and the energy levels of thissystem. The analytical expression of the third-harmonic generation coe?cient is obtainedby using the compact density-matrix approach and the iterative method. We can find thatthe applied electric field and the size of the quantum dots both can change the magnitudeof the third-harmonic generation.In the fourth chapter, the third-harmonic generation(SHG) for cylindrical quantumdots with the static magnetic field is theoretically investigated. In the e?ective massapproximation, we lay out the expression of the wave function and the energy levels ofthis system. The analytical expression of the third-harmonic generation coe?cient isobtained by using the compact density-matrix approach and the iterative method. Wecan find that the static magnetic field and the size of the quantum dots both can changethe magnitude of the third-harmonic generation.In the last chapter, summary of the paper and the main results are given, the shortageand further research are also mentioned.