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结构。各自状态的本征能包括薄区域的负移，但它们跃迁到每个状态在特定厚度的上极化子的能量。如果在这些跃迁发生之前，与各自状态相关的内部场分量发生共振增强，则会出现较大的非线性响应。在较厚的情况下，包括非偶极子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的时间分辨反射率测量，验证了辐射衰减率与理论预测的GaAs层数成正比。(3)在纳米尺度薄层中，由于内部场的纳米尺度空间结构，我们发现了光学双稳定性，并且由于纳米尺度偏振取向配置，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.