Development of Optical Recording System Based on the Local-Field Control

涉及有机染料的光学记录通常是基于染料分子本身的光谱变化，如光异构作用下的光致变色。因此，染料分子的设计和合成至关重要，这可能是一项艰巨的任务。本研究的目的是了解局部场对染料分子光谱的影响，并将其用于光学记录。本项目分为两部分；一个是为了从实验和理论上理解局部场，两个是为了证明效果。样品制备：主要采用Langmuir-Blodgett （LB）技术和真空沉积技术。提出了一种不使用扩散溶剂的新型LB法。局部场测量：使用二次谐波产生（SHG）效率来评估局部场对染料光谱的贡献。电吸收的测量是用来估计电热聚合物的局部场因子。理论：用简单的分子层模型解释第2节的实验数据。将染料j聚集体作为具有极强局域场的模型体系。成功地再现了吸收光谱、发射光谱和共振瑞利散射光谱，表明我们的模型是真实的。演示：利用LB技术制备了铁电聚合物和染料的层状结构。在残余场的驱动下，很容易观察到几个百分点的吸收变化。

The optical recording involving the organic dyes is usually based on the spectral change of the dye molecule itself, e.g., photochromism under photo-isomerization. Therefore, the design and synthesis of the dye molecule is of prime importance which could be a hard task. The purpose of the current study is to understand the effect of the local field on the spectrum of a dye molecule and use it for the opptical recording instead. The project is devided into two parts ; one for understanding the local field both experimentally and theoretically and two for demonstrating the effect.1.Sample Preparation : The Langmuir-Blodgett (LB) techniques are mainly used along with the vacuum deposition. A novel LB method without using a spreading solvent has been developed for the indissoluble molecules.2.Local-Field Measurement : The second-harmonic generation (SHG) dfficiency is used to evaluate the local-field contribution to the dye spectrum. The electroabsorption is measured to estimate the local-field factor in gerroelectric polymers.3.Theory : A simple molecular layr model is used to interprete the experimental data in Sec.2.The J-aggregate of dyes has been taken as a model system with the extremely strong local field. The successful reproduction of the absorption, emission, and the resonance Rayleigh scattering spectra shows that our model is realistic.4.Demonstration : Layred structures of ferroelectric polymers and dyes are fabricated using the LB technique. The absorption change of a few % driven by the remanent field can be seasily observed.