A U.S.-New Zealand Collaborative Study of the Infrared Properties of Crystals

该奖项支持康奈尔大学原子物理实验室和材料科学中心的A.J.西弗斯博士访问新西兰克赖斯特彻奇的坎特伯雷大学，与J.A.坎贝尔博士合作研究玻璃晶体的红外特性。玻璃晶体代表了一种新的材料体系，在该体系中可以探索玻璃在固体中行为的普遍特征。虽然X射线衍射表明晶体在玻璃态下保持了其长程有序，但低温热力学测量表明，另一个低能谱似乎与玻璃中的相同。坎贝尔博士建议生长和表征玻璃状的Ba(1-x)La(X)F(2+x)晶体，其中x从0.001到0.46变化，以便玻璃参数以系统的方式改变。西弗斯博士建议在这些系统上进行持续的红外光谱烧孔测量，以比较低位非平衡态的浓度和热力学玻璃态的浓度。这种持续红外光谱烧孔技术的应用将为研究和量化玻璃中低激发态的物理特性提供一种新的方法。这些实验还可能对影响光学材料应用的过程有一个新的理解，如激光玻璃中光激发的弛豫行为和玻璃中高密度光存储的持久性。

This award supports a visit by Dr. A.J. Sievers of the Laboratory of Atomic Physics & Materials Science Center of Cornell University to the University of Canterbury in Christchurch, New Zealand, to work with Dr. J.A. Campbell on a study of the infrared properties of glassy crystals. Glass crystals represent a new materials system in which the universal character of glass behavior in solids can be probed. Although X-ray diffraction shows that crystal retains its long range order in the glassy state, low temperature thermodynamic measurements show that an additional low energy spectrum appears identical to that found in glasses. Dr. Campbell proposes to grow and characterize glassy Ba(1-x)La(x)F(2+x) crystals where x is varied from 0.001 to 0.46 so that the glass parameter is altered in a systematic manner. Dr. Sievers proposes to carry out persistent IR spectral hole burning measurements on these systems to compare the concentration of low lying nonequilibrium states to the concentration of thermodynamic glassy states. This proposed application of the persistent IR spectral hole burning technique will provide a new methodology for investigating and quantifying the physical characteristics of the low lying states in glasses. These experiments may also lead to a new understanding of processes influencing optical materials applications such as the relaxation behavior of optical excitations in laser glasses and the permanence of high density optical storage in glassy hosts.