Infrared-visible mueller-matrix ellipsometer

我们研究计划的重点是描述固体表面和附着在这些表面上的生物分子之间的分子水平相互作用。对这些现象的更好理解将导致用于植入的生物兼容材料的进步，更高效的生物传感器和生物诊断工具的开发，并增加我们对遇到外来物质时蛋白质天然结构变化的基本知识。这种表征的挑战在于问题的复杂性--有许多环境因素对生物分子表面的结构起作用。提高理解的第一步是能够准确地描述这些分子的吸附结构。光谱技术是探测这些结构的最强大的工具之一，因为它们是非侵入性、非破坏性的，并且可以探测许多可以用光寻址的环境。然而，这样的方法需要详细了解这些材料的光学常数。*红外区域为结构研究提供了特殊的机会，因为分子的局部部分可能被探测。然而，这也是光学常数相对未知的领域。所要求的仪器是红外可见米勒矩阵椭偏仪。它将允许同时测定样品在整个感兴趣的波长范围内的厚度和复折射率，用于化学鉴定和结构分析。此外，这种最先进的仪器的拟议配置将允许表征有序分子和粗糙表面。

The focus of our research program is to describe the molecular-level interaction between solid surfaces and biomolecules attached to these surfaces.  A better understanding of these phenomena will lead to advances in biocompatible materials for use as implants, the development of more efficient biosensors and biodiagnostic tools, and increase our fundamental knowledge of alterations to the native structure of proteins when then encounter foreign materials.  The challenge in such characterization lies in the complexity of the problem---there are many environmental factors that contribute to the biomolecules' structure on a surface. The first step towards an increased understanding is to be able to accurately describe the adsorbed structure of these molecules.  Spectroscopic techniques are among the most powerful tools for probing these structures, since they are non-invasive, non-destructive, and may probe many environments that are addressable by light.  Such methods, however, require a detailed knowledge of the the optical constants of these materials.  The infrared region offers special opportunites for structural studies since localized parts of molecules may be probed.  However, this is also the region in which optical constants are relatively unknown.  The requested instrument is an infrared-visible Mueller-matrix ellipsometer.  It will allow for a simultanous determination of a sample's thickness and complex refractive index over the complete range of wavelengths of interest for chemical identification and structural analysis.  Moreover, the proposed configuration of this state-of-the-art instrument will allow characterization of ordered molecules and rough surfaces.