RUI: Rare Earth Ions in Glasses

小行星9701576 这是一个本科院校的更新项目。 本工作主要研究氟磷酸盐玻璃中三价和二价离子的稳定性以及价态对激发态相干性的影响。 该项目的动机是最近测量异常长的相干时间 三价铕 氟磷酸 为高功率激光应用开发的玻璃。 二价铕离子在这种玻璃中是稳定的，但可以被强烈的紫外光电离成三价离子。 二价离子在稀土离子中是不常见的，但在某些晶体和玻璃中对镱、钐和铕是稳定的。 我们将研究不同价态的稳定性， 光电离过程和激发电子的相干时间 氟磷酸盐玻璃中这三种离子的状态。 %这是研究玻璃中稀土离子荧光的更新项目。稀土离子在激光器、光存储器等光学器件中起着重要的作用。 当离子在不同的电子态之间跃迁时，它们吸收并发射光。 这些跃迁的频率带宽是决定光学器件性能的重要参数。 带宽越窄，基于数据的频率编码的光学存储器的存储容量越大。PI最近发现，稀土铕的发射带宽可以降低 通过从二价离子开始并通过使用强UV光的光电离去除一个电子以产生三价离子。 PI将研究铕和其他以二价态出现的稀土离子，以确定光电离对光学跃迁带宽的影响。 ***

9701576 Brundage This is a renewal project from an undergraduate institution. The proposed work is a study of the stability of trivalent and divalent ions in fluorophosphate glasses and the effect of valence on the coherence of excited states. The project is motivated by recent measurements of unusually long coherence times for trivalent europium in fluorophosphate glasses developed for high-power laser applications. The divalent europium ion is stable in this glass, but can be photoionized to the trivalent ion by intense UV light. The divalent ion is unusual for rare-earth ions, but is stable for ytterbium and samarium as well as europium in some crystals and glasses. We will investigate the stability of different valences, the photoionization process, and the coherence times of excited electronic states for these three ions in fluorophosphate glasses. %%% This is a renewal project for the study of the fluorescence of rare earth ions in glasses. Rare earth ions play an important role in many optical devices, such as lasers and optical memories. The ions absorb and emit light when they make transitions between different electronic states. The frequency bandwidth f these transitions is an important parameter in determining the performance of optical devices. The narrower the bandwidth the greater the storage capacity of an optical memory based on frequency coding of data. The PI recently discovered that the bandwidth of the emission of the rare earth europium can be decreased by starting with divalent ions and removing one electron by photoionization using intense UV light to produce trivalent ions. The PI will study europium and other rare earth ions that occur in the divalent state to determine the effect of photoionization on the bandwidth of optical transitions. ***