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Resonance of Electronic States and Optical Non-linearity in Coupled Quantum Well Structures

耦合量子阱结构中的电子态共振和光学非线性

基本信息

批准号：
05452112
负责人：
SAWAKI Nobuhiko
金额：
$ 4.22万
依托单位：
NAGOYA UNIVERSITY
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (B)
财政年份：
1993
资助国家：
日本
起止时间：
1993 至 1995
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/en/grant/KAKENHI-PROJECT-05452112/
关键词：
Coupled Quantum Well Resonance of Electronic States Optical Nonlinearity Wave Mixing Photoluminescence Optical Absorption Exiton Modulator デルタドープ構造ホトルミネッセンス

项目摘要

The purpose of the research is to clarify the optical nonlinearity in a strongly coupled triple quantum well structure, where the application of an external field changes the situation of resonance of the electronic states. Thus the exciton oscillator strength should be a strong function of the external field. Since the electrons and holes have different tunneling escape times, after the excitation of carriers in a well by a femtosecond laser pulse, electrons will escape to the other well faster than holes, resulting the build up of internal field across the wells. This induced field could affect the change of the oscillator strength of excitons. Since the induced field will increase by increasing the input optical power, we can expect strong optical nonlinearity which will be responsible in the femtosecond region.A GaAs/AlGaAs triple quantum well structure was made by MBE on a semiinsulating GaAs. The optical spectra was investigated using femtosecond laser pulse. The transmission of the laser light through the sample was investigated at various wave lengths. The transmittance was found to be a strong function of the input intensity. Above a critical power, the transmittance is decreased as the increase of the input power. The nonlinear behavior is enhanced near the anti-crossing energy associated with the triple resonance, which is in good agreement with the theoretical prediction.

研究的目的是阐明强耦合三量子阱结构中的光学非线性，其中施加外场改变了电子态的共振情况。因此激子振子强度应该是外场的强函数。由于电子和空穴的隧穿逃逸时间不同，飞秒激光脉冲激发一个阱中的载流子后，电子会比空穴更快地逃逸到另一个阱，从而导致跨威尔斯的内部场的建立。这种诱导场可以影响激子振子强度的变化。由于入射光功率的增加会导致诱导场的增加，因此在飞秒区会产生很强的非线性光学效应。利用分子束外延技术在半绝缘GaAs衬底上制备了GaAs/AlGaAs三量子阱结构。利用飞秒激光脉冲研究了其光谱特性。在不同波长下研究了激光通过样品的透射率。发现透射率是输入强度的强函数。在临界功率以上，透射率随输入功率的增加而减小。在三重共振的反交叉能附近，非线性行为增强，这与理论预测相一致。