Investigation of Infra Red Spectral Persistence in Condensed Matter

凝聚态物质中红外光谱余辉的研究

• 批准号: 9312381
• 负责人: Albert Sievers
• 金额: --
• 依托单位: Cornell University
• 依托单位国家: 美国
• 项目类别: Continuing grant
• 财政年份: 1993
• 资助国家: 美国
• 起止时间: 1993-12-15 至 1997-05-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=9312381&HistoricalAwards=false
• 关键词: Investigation; Infra; Red; Spectral; Persistence

9312381 Sievers Persistent spectral hole burning will be investigated in chalcogenide glasses, polymers, and poled ferroelectrics. A ternary chalcogenide glass will be used to distinguish processes which are controlled by the glass topology from those which are dominated by the chemistry of the chalcogen (primarily Se) chemistry. The influence of network topology on short time energy transfer and the homogeneous dephasing time will be measured by infrared picosecond pump-probe and photon echo experiments, respectively. The focus in these studies is to determine the effect of the average coordination number on the short time dynamics. Polymers will be investigated at very low temperatures to inhibit thermally activated recovery to the vibrational ground state. Poled ferroelectrics will be studied by reorienting the polar molecules by persistent hole burning in the opposite direction to the crystal polarization. In a related study, the nature of localized vibrational modes will investigated in various types of crystals containing defects. In these materials localized modes may be trapped at a defect site leading to persistent changes in the defect absorption spectrum at low temperatures. %%% The absorption of light in a glass can be altered when a laser beam is incident on the same region of the glass. The glass retains a memory of the laser light. This memory effect is termed "spectral hole burning" because the optical absorption is reduced precisely for the same light energy corresponding to the laser energy. Study of the "spectral hole" as a function of temperature, time and light energy provides important information about microscopic structural properties of the glass. The proposed study will extend the investigation of this effect to ultrashort time scales and to imperfect crystalline solids. The aim of such studies is to modify a solid in order to observe these hole burning effects at room temperature with the potential application as optical mem ory devices. ***

9312381 Sievers 将研究硫族化物玻璃、聚合物和极化铁电体中的持续光谱烧孔。 三元硫属化物玻璃将用于区分由玻璃拓扑控制的过程与由硫属元素（主要是 Se）化学控制的过程。 网络拓扑对短时能量传输和均匀相移时间的影响将分别通过红外皮秒泵浦探针和光子回波实验来测量。 这些研究的重点是确定平均配位数对短时动态的影响。 将在非常低的温度下研究聚合物以抑制热激活恢复到振动基态。 将通过在与晶体极化相反的方向上持续烧孔来重新定向极性分子来研究极化铁电体。 在相关研究中，将研究各种类型的含有缺陷的晶体的局域振动模式的性质。 在这些材料中，局域模式可能被捕获在缺陷位置，导致低温下缺陷吸收光谱的持续变化。 %%% 当激光束入射到玻璃的同一区域时，玻璃中的光吸收会发生变化。 玻璃保留了激光的记忆。 这种记忆效应被称为“光谱烧孔”，因为对于与激光能量相对应的相同光能量，光学吸收精确地减少。 对“光谱孔”作为温度、时间和光能函数的研究提供了有关玻璃微观结构特性的重要信息。 拟议的研究将对这种效应的研究扩展到超短时间尺度和不完美的结晶固体。 此类研究的目的是修改固体，以便观察室温下的这些烧孔效应以及作为光学存储器件的潜在应用。 ***