Study of size dependence of optical response due to nanoscale spatial structure of the response field

(1)从理论上阐明了薄膜中辐射与激子耦合系统的模式结构。各个态的本征能量包括薄区的负移，但对于每个态，它们跃迁到特定厚度的上极化子的能量。如果与相应状态相关的内场分量的共振增强发生在这些跳跃之前，则出现大的非线性响应。对于较厚的情况，包括非偶极子类型激子态在内的较高能级的辐射衰减常数变得非常大。(2)通过对多层GaAs层的时间分辨反射测量，我们验证了辐射衰减率与理论预测的层数成正比增加。(3)由于内场的纳米级空间结构，我们发现了纳米薄膜中的光学双稳性，由于纳米级的偏振取向组态，我们发现了新的光函数。

(1) We have theoretically clarified the mode structure of the coupled system of the radiation and the excitons confined in a thin film. The eigenenergies of the respective states include the negative shift at thin region, but they jump to the energies of the upper polaritons at a particular thickness for each state. If the resonant enhancement of the components of internal field associated with the respective states occurs before these jumps, the large nonlinear response appears. For the thicker case, the radiative decay constant becomes very large for the higher levels including the non-dipole type excitonic states.(2) By the time-resolved reflectance measurement of the GaAs multiple layers, we have verified that the radiative decay rate increases in proportion to the number of GaAs layers as predicted in the theory.(3) We have found the optical bistablity in nanoscale thinflim due to the nanoscale spatial structure of the internal field, and the novel photofunctions due to the nanoscale polarization orientation configurations.