Theoretical study on optical process in nanomaterial by using nonlinear susceptibility without cancellation terms

无抵消项非线性磁化率理论研究纳米材料光学过程

基本信息

批准号：
16540287
负责人：
AJIKI Hiroshi
金额：
$ 2.3万
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：
2004
资助国家：
日本
起止时间：
2004 至 2006
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-16540287/
关键词：
third-order optical nonlinearity microcavity cavity QED biexciton entangled photon pair quantum well quantum dot 3次非線形応答光学カー効果

项目摘要

In the ordinal expression of optical nonlinear susceptibility, many terms are cancelled with each other. If we leave the cancellation terms, the nonlinear susceptibility diverges in a bulk limit. In order to avoid this unphysical result, we should treat the cancellation problem carefully. So far, the cancellation problem was exactly treated in a simple model by Ishihara and Cho. However, it is almost impossible to remove the cancellation terms in the first principle calculation by usin the ordinal expression of the nonlinear susceptibility.In this project, we have succeeded to derive a general expression of nonlinear susceptibility without cancellation terms in advance. The general expression helps us to calculate size dependence of nonlinear susceptibility without attention to the cancellation terms.We have also studied optical nonlinear response of excitons in microcavity. So far, the optical nonlinearities of cavity systems were studied in a semiclassical treatment. However, we have shown that cavity quantum electrodynamics (cavity QED)is indispensable in order to study the optical nonlinearity of the cavity systems. Then, we study various nonlinear processes in the cavity QED treatment.1.We have derived optimal conditions for achieving large optical nonlinearity of a single quantum dot in microcavity.2.We have studied entangled photon generation due to the hyper-parametric process from a quantum well and quantum dot in microcavity. The efficiency of the generation is dramatically enhanced due to the cavity effect. We have also found optimal conditions for the entangled photon generation. These optimal conditions are qualitatively understood from the characteristic feature of the cavity QED.

在光学非线性磁化率的序数表达式中，许多项相互抵消。如果我们保留取消项，非线性磁化率会在体积极限内发散。为了避免这种非物理结果，我们应该谨慎对待取消问题。到目前为止，Ishihara 和 Cho 在一个简单的模型中准确地处理了取消问题。然而，利用非线性磁化率的序数表达式去除第一性原理计算中的抵消项几乎是不可能的。在本项目中，我们成功地推导了一个无需预先抵消项的非线性磁化率的通用表达式。通用表达式有助于我们计算非线性磁化率的尺寸依赖性，而无需考虑抵消项。我们还研究了微腔中激子的光学非线性响应。到目前为止，腔系统的光学非线性是通过半经典处理来研究的。然而，我们已经证明，为了研究腔系统的光学非线性，腔量子电动力学（腔QED）是必不可少的。然后，我们研究了腔 QED 处理中的各种非线性过程。1.我们推导了微腔中单个量子点实现大光学非线性的最佳条件。2.我们研究了由于超参数过程而产生的纠缠光子。微腔中的量子阱和量子点。由于空腔效应，发电效率显着提高。我们还找到了纠缠光子产生的最佳条件。这些最佳条件可以从腔 QED 的特征中定性地理解。