Materials World Network: Infrared Glass and Glass-Ceramics with New Optical and Mechanical Functionalities.

由亚利桑那大学材料科学系和法国雷恩大学化学系的学生和教职员工组成的国际研究团队通过在非常低的声子纳米晶体环境中掺入活性稀土离子来开发高效发光微晶玻璃。众所周知，低声子环境会大大降低电子-声子耦合，从而导致高辐射发射率和高荧光强度。硫系微晶玻璃系统通过将活性稀土离子加入到一系列重碱卤化物或金属卤化物纳米晶环境中，提供了调节活性稀土离子环境的可能性。该项目建立在美国和法国在这些系统的化学和热力学方面的联合专业知识的基础上，以合成和表征具有高效荧光特性的纳米复合材料。这些微晶玻璃的另一个显着优势是能够优化光学性能，同时保留玻璃基质的成形性，以便生产纤维。硫系微晶玻璃在红外领域具有广泛的透明性，这为通信放大器和中红外激光光源等应用开辟了道路。然后选择硫化物玻璃基质，以便在考虑到近红外和中红外的特定应用的稀土发射范围内提供最佳透明度。这项研究有可能引发红外光子技术的飞跃。高效发光材料为开发用于芯片实验室应用的微型激光光源或用于光纤到户电信传输的放大器提供了可能性。特别是，随着最近无羟基二氧化硅的发展，电信波段已经从1.2微米扩大到1.7微米，因此需要比传统Er3+更宽的稀土发射波长范围。然而，在该临界范围内的大多数稀土发射体，如Pr3+、Tm3+和Dy3+，在氧化物玻璃中的效率都很低。因此，这些离子的低声子矩阵的发展将允许广泛地提高承载信息的电信网络的容量。此外，这项研究工作与一个旨在使博士生受益的国际教育计划完全整合在一起。研究生在两所大学轮流从事课程工作和研究活动，并获得双博士文凭。

An international research team of students and faculty in the Materials Science Department at the University of Arizona and the Chemistry Department at the University of Rennes, France, develops high-efficiency luminescent glass-ceramics by incorporating active rare-earth ions within a very low phonon nanocrystalline environment. Low phonon environments are known to strongly reduce electron-phonon coupling which results in high radiative-emission rates and high fluorescence intensity. Chalcogenide glass-ceramics systems offer the possibility of tuning the environment of active rare-earth ions by incorporating them into a range of heavy alkali-halide or metal-halide nanocrystalline environments. The project builds upon joint expertise in the US and France in the chemistry and thermodynamics of these systems to synthesize and characterize nano-composite materials with high-efficiency fluorescent properties. Another notable advantage of these glass-ceramic is the ability to optimize the optical properties while retaining the formability of the glassy matrix in order to produce fibers. Chalcogenide glass-ceramics posses an extensive transparency over the infrared domain which opens the way for many applications such as telecom amplifiers and mid-infrared laser sources. The chalcogenide glass matrix is then selected such as to offer optimal transparency in the range of rare-earth emission considered for specific applications in the near- and mid-infrared.This research has the potential to induce a leap forward in infrared photonic technology. High-efficiency luminescent materials open the possibility to develop miniature laser source for lab-on-chip applications or amplifiers for fiber-to-the-home telecom delivery. In particular, with the recent development of OH-free SiO2, the telecom band has opened up from 1.2 to 1.7 microns and consequently requires a wider range of rare-earth emission wavelengths than the conventional Er3+. However, most rare-earth emitters in that critical range such as Pr3+, Tm3+ and Dy3+ are highly inefficient in oxide glasses. Hence the development of low phonon matrixes for these ions will permit to widely improve the capacity of information-carrying telecommunication networks. In addition, this research effort is fully integrated with an international educational program designed to benefit PhD students. Graduates students perform course work and research activities alternately at both universities and obtain a double PhD diploma.