Finite Difference Time Domain Analysis Of The Effect Of Electromagnetic Fields On Nanostructures

With the development of information technology,the size of electronic devices reaches the nanoscale.In this case,macroscopic and microscopic theories need to be combined to analyze the physical problems of nanoscale.In general,the study of these nano-sized devices contains the coupling problem of the quantum-electromagnetic effect.In this thesis,the semi-classical Maxwell-Schrodinger coupling method is used to analyze some quantum-electromagnetic coupling problems,including the quantum-electromagnetic effect of nanofilms and the quantum state controlling of nanotubes.Firstly,the Maxwell-Schrodinger coupling method is used to analyze the interaction between the electromagnetic field and nanofilms.The current distribution of the surface ordered and disordered nanofilms are characterized by the resonance potential well and the non-resonant potential well,respectively.For the surface ordered nanofilms,the characteristic of the polarized current is periodic oscillation;For surface disordered nanofilms,the characteristic of the polarized current is disorganized.At the same time,the influence of strong field irradiation and weak field irradiation on the nanofilms is analyzed.For non-resonant potential well,the electron wave packet is more likely to be diffused by the strong field irradiation.Then,D'Alembert-Schrodinger coupling solution method is used to analyze the quantum-electromagnetic coupling problem.Compared with the above Maxwell-Schrodinger hybrid method,the electric field and magnetic field do not need to be solved in this method.Therefore,the computation time and memory can be saved.In the end,the process of quantum state transition in nanotubes is presented in this paper.The quantum state can not be converted perfectly by the incident electromagnetic pulse without considering the coupling of the radiated electromagnetic field,which is caused by the polarized current.For considering the coupling effect of the radiated electromagnetic field,the process of quantum state transition can be realized perfectly.Finally,this control method is used to analyze the perfect conversion of multiple quantum states.