Laser Spectroscopy of Ferroelectrics and Dynamics of Phononsin Glasses and Crystalline Fibers

这项提议是为了扩大圣彼得堡约夫研究所的俄罗斯研究小组和乔治亚大学的美国激光光谱学小组之间的合作研究。目前在单晶光纤声子动力学方面的合作将扩大到包括玻璃声子动力学和高分辨率激光光谱学在铁电体研究中的应用。拟议的研究将使俄罗斯研究人员在铁电体声子动力学和光谱学方面的专业知识与格鲁吉亚大学最先进的设备和激光光谱学专业知识相匹配。这些设施包括一个利用激光加热基座生长技术制备单晶纤维的系统，用于单色声子产生的线可调谐脉冲远红外激光器和用于相干瞬态和光谱烧孔光谱的单频可调谐染料激光器。本研究工作的预期结果将提供关于铁电掺铬锗酸锂玻璃中使用光子门控光电离烧孔的畴结构和光学烧孔存储器的可能性的信息，以及关于玻璃的空间、光谱和时间声子动力学的信息。利用单晶纤维的特殊几何结构，更好地理解声子-表面相互作用和晶体中的声子输运。本研究处理材料科学中的三个基本问题。第一个项目将是研究无序材料（如玻璃）中高频声子的动力学。这个问题涉及到对玻璃系统的热传递、结构和动力学的理解。第二个项目将是利用最先进的高分辨率激光光谱技术研究铁电材料的畴结构。这项工作的结果将为铁电材料的基本性质提供新的信息。最后，将研究含有已知杂质的铁电材料作为高密度光学计算机存储器的新候选材料。这项研究将由乔治亚大学的美国激光光谱学小组和圣彼得堡约夫研究所的俄罗斯研究小组合作进行。它将利用佐治亚大学在高分辨率激光光谱学、远红外激光器和材料制备能力方面的专业知识和设施，利用激光加热基座生长，再加上Ioffe研究所在铁电体的性质和制备方面的专业知识，以及他们在玻璃声子研究方面的经验。

This proposal is to extend a collaborative research effort between the Russian research group at the Ioffe Institute in St. Petersburg and the U.S. laser spectroscopy group at the University of Georgia. The current cooperation in phonon dynamics in single crystal fibers will be broadened to include the dynamics of phonons in glasses and into the application of high resolution laser spectroscopy to the study of ferroelectrics. The proposed research will match the expertise of the Russian investigators in phonon dynamics and spectroscopy of ferroelectrics with the state-of-the-art facilities and expertise in laser spectroscopy at the University of Georgia. These facilities include a system for the preparation of single crystalline fibers using the techniques of laser-heated pedestal growth, a line tunable pulsed far infrared laser for monochromatic phonon generation and a single frequency tunable dye laser for coherent transient and spectral hole-burning spectroscopy. The anticipated results for this research effort will provide information on the domain structure and the possibility for optical holeburning memories in the ferroelectric chromium doped lithium germanate glasses using photon-gated photoionization holeburning, information on the spatial, spectral and temporal phonon dynamics of glasses, and a better understanding of phonon-surface interactions and phonon transport in crystals using the special geometry of single crystalline fibers. %%% This study treats three basic problems in materials science. The first project will be to examine the dynamics of high frequency phonons in disordered materials such as glasses. This problem relates to the understanding of heat transport, the structure, and the dynamics of glassy systems. The second project will be to study the domain structure of ferroelectric materials using state- of-the-art high resolution laser spectroscopy. The results of this exercise should provide new information on the fundamental properties of ferroelectric materials. Finally, ferroelectric materials containing known impurities will be investigated as possible new candidates for high density optical computer memories using persistent optical holeburning. This research will be conducted as a collaborative effort between the U.S. laser spectroscopy group at the University of Georgia and the Russian research group at the Ioffe Institute in St. Petersburg. It will utilize the expertise and facilities at the University of Georgia in high resolution laser spectroscopy, far infrared lasers and materials preparation capabilities using laser heated pedestal growth coupled with the expertise at the Ioffe Institute in the properties and preparation of ferroelectrics and their experience with phonon studies in glasses.