Collaborative Research/GOALI: Engineered Crystallization Behavior of Phase Change Materials to Enable Advanced Optical Functionalities

非技术描述：可调谐光学元件，其性质可以改变以实现不同的物理和光学行为，对于从光谱到成像的各种应用都具有广泛的兴趣。 这些组件中的大多数牺牲光学性能以获得可调谐性，并且它们使用难以封装的结构和工艺制造。 在这个合作项目中，来自中央佛罗里达大学、宾夕法尼亚州立大学和洛克希德·马丁公司的研究人员正在优化红外硫属化物材料和纳米结构，这些材料和纳米结构表现出可逆的非晶到结晶相变，以具有定制的折射率值和连续可调的色散特性。 这种硫属化物相变材料的可用性将使得能够通过利用与相变相关联的异常大的折射率变化来开发新的紧凑的可调谐光学部件。 硫属化物材料和工艺正在开发的这个项目是广泛提供通过NSF资助的国家纳米技术基础设施Network.Technical描述：光学材料与组合定制的性能，是光谱可调和可逆的是有吸引力的生产光学元件具有独特的功能。 硫系相变材料（PCM）响应于脉冲热、光或电刺激而表现出快速且可逆的非晶-结晶相变。 然而，目前基于硫属化物PCM的光学器件仅利用了与材料的纯非晶态和纯晶态之间的转变相关联的光学反射率的大变化。 在这个合作项目中，来自中央佛罗里达大学、宾夕法尼亚州立大学和洛克希德·马丁公司的研究人员正在进行实验研究，以确定一种硫属化物组合物，该组合物能够控制空间分散纳米晶体的成核和生长，这将在复合玻璃陶瓷材料的红外折射率和色散中产生连续可调和可再现的变化。 对于每一种组合物，散装，薄膜，和纳米图案化的膜被表征，以了解由外部光或热激发引起的成核和生长过程中的设备相关的边界条件的作用。 互补技术正在应用于理解内在材料响应和定制的光学性能之间的基本关系，包括热，结构和光学测量和分析。 该项目期间收集的结构-性能数据将提供使用硫属化物PCM设计完全可调谐光学元件所需的关键输入。 一个新的指导团队计划，连接大学和行业合作研究人员，培训研究生和本科生拥有全球相关的劳动力技能。 硫族化物相变材料和工艺正在开发的这个项目是提供给更广泛的外部学术界和工业界通过国家科学基金会资助的国家纳米技术基础设施网络（NNIN）位于宾夕法尼亚州州立大学。

NON-TECHNICAL DESCRIPTION: Tunable optical components, ones where their properties can be altered to realize different physical and optical behavior, are of widespread interest for diverse applications ranging from spectroscopy to imaging. Most of these components sacrifice optical performance for tunability and they are manufactured using structures and processes that are difficult to miniaturize. In this collaborative project, researchers from the University of Central Florida, Pennsylvania State University, and Lockheed Martin are optimizing infrared chalcogenide materials and nanostructures that exhibit reversible amorphous-to-crystalline phase transitions to have tailored refractive index values and dispersive properties that are continuously tunable. The availability of such chalcogenide phase change materials will enable the development of new compact, tunable optical components by exploiting the exceptionally large refractive index change associated with the phase transition. The chalcogenide materials and processes being developed in this project are broadly available through the NSF-funded National Nanotechnology Infrastructure Network.TECHNICAL DESCRIPTION: Optical materials with compositionally tailored properties that are spectrally tunable and reversible are attractive for producing optical components with unique functionalities. Chalcogenide phase change materials (PCMs) exhibit rapid and reversible amorphous-to-crystalline phase transitions in response to pulsed thermal, optical, or electrical stimuli. However, current optical devices based on chalcogenide PCMs have only exploited the large change in optical reflectance associated with the transition between the pure amorphous and the pure crystalline states of the material. In this collaborative project, researchers from the University of Central Florida, Pennsylvania State University, and Lockheed Martin are conducting experimental studies to identify a chalcogenide composition that enables controlled nucleation and growth of spatially dispersed nanocrystals, which will produce a continuously tunable and reproducible change in the infrared refractive index and dispersion of the composite glass ceramic material. For each composition, bulk, thin film, and nanopatterned films are being characterized to understand the role of device-relevant boundary conditions on the nucleation and growth process induced by external optical or thermal excitation. Complementary techniques are being applied to understand the fundamental relationship between the intrinsic material response and the tailored optical performance, including thermal, structural, and optical measurement and analysis. The structure-property data being collected during this project will provide the critical input needed to design fully tunable optical components using chalcogenide PCMs. A new mentoring team program, which links university and industry partnered researchers, trains graduate and undergraduate students to have globally-relevant workforce skills. The chalcogenide phase change materials and processes being developed in this project are available to the broader external academic and industrial community through the NSF-funded National Nanotechnology Infrastructure Network (NNIN) located at Pennsylvania State University.