Molecular assemblies for ultrafast nanophotonics

本项目主要研究了几种有序分子组装体（包括尺寸量子化的CdS纳米颗粒和离子对电荷转移复合物）的超快光响应的构建和检测、有机分子激发态非线性光学性质的评价以及此类光响应材料在全光数据处理中的应用。来自澳大利亚、德国和日本的科学家合作进行了这项研究，主要目标是：1）在阴离子聚合物膜和水溶液中形成尺寸量子化和高发光的CdS纳米颗粒; 2）控制CdS纳米颗粒的尺寸和表面处理，以大大减少缺陷或陷阱; 3）通过飞秒（fs）激光闪光光解测量超快光响应，并检查尺寸和表面调节对光响应的动力学的影响; 4）包含这些的新颖导波模式几何结构的构造 ...更多信息 光响应材料，以便将它们应用于基于光致吸收、折射率或发光的超快变化的并行光学数据处理。这将有助于在不久的将来构建基于有机分子和无机纳米粒子的超快光响应的全光数据处理。直径为3.7-5.4 nm的颗粒在水溶液中显示出非常强的激子发光和没有或非常弱的缺陷发光（如果有的话）。（τ<0.7ps）飞秒激光激发发光激活CdS纳米颗粒后激子漂白后的恢复分量。3）二阶非线性光学常数的评估，4）在ns-fs激光激发时通过包含有机染料的导模几何结构对反射光的超快平行光学调制的证明。少

This project dealt primarily with the construction and examination of ultrafast photoresponses of several organized molecular assemblies, including size-quantized CdS nano-particles and ion-pair charge-trans- fer complexes, evaluation of nonlinear optical properties of organic molecules at the excited state and also with application of such photoresponses materials in all-optical data processing. Scientists from Australia, Germany and Japan collaborated in this study, with the main objectives being,1) Formation of size-quantized and highly luminescent CdS nano-particles in anionic polymer films, and in aqueous solutions ; 2) Control of CdS nano-particle sizes and their surface treatments to considerably decrease defects or traps ; 3) Measurement of ultrafast photoresponses by femtosecond (fs) laser flash photolysis, and an examination of the effect of size and surface conditioning on the dynamics of the photoresponse ; 4) Construction of novel guided wave mode geometry containing these … More photoresponsive materials in order to apply them in parallel optical data processing based on photoinduced ultrafast changes of absorption, refractive index or luminescence.Followings are some of main results obtained from the present study, which will contribute a great deal to construct all-optical data processing in the near future based on ultrafast photoresponses of organic molecules and inorganic nano-particles.1) Preparation of CdS nano-particles with a diameter of 3.7-5.4 nm showing very strong exciton lumines- cence and none or very weak, if any, defect luminescence in aqueous solutions.2) Observation of an extremely fast (τ<0.7 ps) recovery component after exciton bleaching upon fs laser excitation of luminescence activated CdS nano-particles.3) Evaluation of the second order nonlinear optical constant, hyperpolarizability, at the excited state.4) Demonstration of ultrafast parallel optical modulation of reflected light by guided mode geometry containing organic dyes upon ns-fs laser excitation. Less