Excitonic nonlinearity in inorganic-organic quantum-well materials

我们研究了有机-有机量子阱材料(C6H13NH3)2PbI4和(C4H9NH3)2PbBr4中的激子非线性。众所周知，这些材料具有极大的非线性。我们研究了大非线性的起源，特别是研究了非线性与激子自旋弛豫的关系。研究结果总结如下：(1)利用多个非线性实验，我们发现这些材料的超快自旋弛豫贡献了大的激子非线性。(2)我们研究了自旋弛豫与其他非线性参数之间的关系。结果我们发现，自旋弛豫并不像其他非线性参数那样带来任何尺寸的非线性放大。(3)为了获得更大的非线性，我们必须使用*另一种共振，如极化效应。我们发现，极化效应通过超辐射效应增加了激子的非线性。

We have investigated excitonic nonlinearity in morganic-organic quantum-well materials, (C6H13NH3)2PbI4 and (C4H9NH3)2PbBr4. These materials are known to have extremely large nonlinearity. We investigated the origin of the large nonlinearity; especially we focused on the relationship between the nonlinearity and excitonic spin relaxation. The summary of results is the following;(1) Using several nonlinear experiments we have found that the ultrafast spin relaxation of these materials contributes the large excitonic nonlinearity.(2) We examined the relationship between the spin relaxation and other nonlinear parameters. As a result we have found that the spin relaxation does not bring any size-enhancement of the nonlinearity as the case of other nonlinear parameters.(3) In order to obtain much larger nonlinearity we have to use*another resonance such as polaritonic effect. We have shown that the polaritonic effect increases the excitonic nonlinearity through the supperradiant effect.