Theoretical Research of Optical Pulse Response of Quantum Confined Excitons

量子约束激子光脉冲响应的理论研究

基本信息

批准号：
09640396
负责人：
ISHIHARA Hajime
金额：
$ 2.05万
依托单位：
Osaka University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
1997
资助国家：
日本
起止时间：
1997 至 1999
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-09640396/
关键词：
Nonlinear Optics Optical Pulse Excitons Polaritons Ultra fast response Mesoscopic systems Nano-scale matters Thin film パルス応答

项目摘要

We have developed the theory for the optical response of the ultra short pulse in which the nanoscale spatial structure of the response field in the media is correctly considered. This theory has following features.The nonlocal response is considered.The microscopic position dependences of the induced current density and the response field are correctly taken into account.The self-consistency of the induced current density and the response field are taken into account.Nonlinear response can be treated.We take the method such that the simultaneous equations of Maxwell eq. and the equation for the density matrix of the matter system are numerically solved. Taking the rotating wave approximation and slowly varing envelope approximation in time, and reducing the number of the exctitonic states as bases, we make this calculation feasible. Appling this method to the ultra thin film confining excitons, we have clarified the following points.1.The remarkable nanoscale spatial structure of the response field appears even for the short pulse of several hundreds femto second, and the selection rule that should hold in the case of long wavelength is broken for both the linear and nonlinear regimes. We understand that our approach is essentially necessary in such conditions.2.We elucidate, for the first time, the real time characteristics of the internal field by the short pulse undergoing multiple reflection.3.The time characteristics of the nonlinear signal reflects the above mentioned motion of the internal field in time, thus, the nano-scale spatial structure of the internal field takes a important role in the time characteristics of the nonlinear response. It is also clarified that if we neglect this spatial structure of the internal field, we can not describe the correct time variation of the nonlinear signal at all.

我们已经开发了对超短脉冲的光学响应的理论，在该脉冲中，正确考虑了培养基中响应场的纳米级空间结构。该理论具有以下特征。考虑了诱导电流密度和响应场的微观位置依赖性，并正确考虑了诱导的电流密度和响应场的自符矛盾。我们可以处理Maxwell EQ的同时方程。并且物质系统的密度矩阵的方程是在数值上求解的。将旋转波的近似和缓慢的包膜近似近似，并减少示外状态的数量作为碱基，我们使此计算可行。将此方法涂在限制激子的超薄膜中，我们已经澄清了以下几个点。1。响应场的显着纳米级空间结构甚至对于几百个FEM的短脉冲即使是几百个FEM的短脉冲，并且在长波长的情况下应为线性和非线性状态而损坏的选择规则。我们知道，在这种情况下，我们的方法基本上是必要的。2。我们首次阐明内部场的实时特征通过短暂的脉冲经历多次反射。3。非线性信号的时间特征反映了上述内部字段的上述运动，因此，内部领域的纳米尺度空间结构在内部领域的重要角色中起着非单元性响应的重要作用。还可以澄清的是，如果我们忽略了内部场的这种空间结构，我们将无法完全描述非线性信号的正确时间变化。