CRIF:ID- Development of an Ultrabroad Bandwidth UV-Visible Cavity Enhanced Spectroscopy Spectrometer

这是由CRIF：ID项目授予弗吉尼亚大学化学系凯文·K·莱曼、科罗拉多州立大学机械工程系阿泽尔·亚林和科罗拉多州立大学大气科学系索尼娅·M·克莱登韦斯的奖项。在开发项目中，将设计、制造、测试和表征基于CaF2棱镜的光腔。由于这种材料的瑞利散射低得多，预计这些棱镜将在近紫外区和大部分中紫外区以及可见光区域都有用。这一光谱区域覆盖了大多数分子的最低电子跃迁。与传统的吸收技术相比，这些棱镜的使用将大大提高灵敏度，并可对已知吸收截面的物种进行低至痕量的绝对浓度测定。此外，棱镜腔衰荡光谱系统将与针对分子光谱(Lehmann)、溅射测量(YARIN)和大气气溶胶(Kredenweis)的实验相结合。光谱学是物理科学中使用最广泛的工具之一。紫外、可见光和红外光谱区域的吸收光谱提供了关于分子的分子和电子结构以及它们与其他分子相互作用的信息。在荧光很弱的情况下，吸收是检测光学跃迁的最直接和最实用的方法。虽然吸收光谱被广泛使用，但长期以来，它在许多应用中都存在灵敏度不足的问题。在过去的二十年里，通过引入腔衰荡光谱和利用低损耗(高精细度)光学腔的相关方法，这种灵敏度得到了显著的提高，开辟了许多新的应用。目前的工作将大大提高这些方法的光谱范围和灵敏度，特别是在紫外区。这些项目将由研究生实施，他们将学习有价值的研究和仪器开发技能。

This is an award from the CRIF:ID program to Kevin K. Lehman in the Chemistry Department at the University of Virginia, Azer Yalin, Mechanical Engineering Department, Colorado State University and Sonia M. Kreidenweis, Atmospheric Science Department, Colorado State University. In the development project optical cavities based upon CaF2 prisms will be designed, fabricated, tested and characterized. Because of the substantially lower Rayleigh scattering of this material, it is anticipated that these prisms will be useful throughout the near and much of the mid-UV spectral regions as well as the visible. This spectral region covers the lowest electronic transitions of most molecules. The use of these prisms will allow a dramatic improvement in sensitivity over conventional absorption techniques and absolute concentration determination down to trace levels for species of known absorption cross section. Further, the prism cavity ring-down spectroscopy systems will be integrated with experiments targeted at Molecular Spectroscopy (Lehmann), measurements of sputtering (Yalin), and atmospheric aerosols (Kreidenweis). Spectroscopy is one of the most widely used tools in physical science. Absorption spectroscopy in the UV, visible, and IR spectral regions give information on the molecular and electronic structures of molecules and their interactions with other molecules. In cases where fluorescence is weak, absorption is the most straightforward and practical way to detect optical transitions. While absorption spectroscopy is widely used, it has long suffered from inadequate sensitivity for many applications. In the past two decades, this sensitivity has been dramatically improved, opening up many new applications, by the introduction of Cavity Ring-down Spectroscopy and related methods that exploit low loss (high finesse) optical cavities. The present work will lead to a substantial increase in the spectral range and sensitivity of these methods, particularly in the UV spectral region. The projects will be carried out by graduate students who will learn valuable research and instrument development skills.