摘要
利用简并四波混频研究了一种偶氮苯液晶聚合物的相位共轭和光学记录特性。在近共振条件下，用低功率Nd：YAG倍频激光得到高效率的相位共轭光和高阶衍射光。当光强达到10W／cm2量级时，薄膜显示出光记录效应，即在撤掉写入光之后，相位共轭波并不消失。进一步增大光强到103W／cm2量级时，出现三组分别只与前向泵浦光、后向泵浦光和信号光有关的高阶衍射光。其中观察到第三阶衍射光。且在撤掉任两束光后，所剩一束光的各阶衍射光效率保持不衰减。通过四波混频实验之后，薄膜上出现可长久保存的明亮的全息光斑。用光致异构和光致分子取向重组解释了相位共轭波特性和永久记录效应，并在实验上用可见一紫外吸收光谱证实分子新的取向的存在及其具有的稳定性。
Phase conjugation (PC) and optical storage in a liquid-crystul polymer film were studied by degenerated four-wave mixing. On the basis of resonant absorption,high-efficiency phase conjugated beam was obtained while low-intensity incident waves were used. When intensities of the waves increased to the order of 10 W/cm2, the film showed a behavior of optical storage and high- order diffraction was observed. As intensities of the incident waves reached the order of los W/cm2, three groups of backward and forward high-order diffraction beams were detected. The highest-order diffraction beam was the 3rd-order one. After turning of f two of the incident waves, the high-order diffraction produced by the remained wave didnI t decrease obviously. After the bleaching, a brilliant hologram spot was observed on the film and could be maintained over 120 days under general storage conditions.
出处
《光学学报》
EI
CAS
CSCD
北大核心
1996年第4期454-459,共6页
Acta Optica Sinica
基金
国家自然科学基金
关键词
光学记录
相位共轭
偶氮苯
液晶
optical storage, phase conjugation, liquid-crystal polymer
