Probing Far-Infrared Excitations of Surfaces and Thin Films by Optoelectronic Techniques

在这个项目中，作为光学科学与工程多学科研究跨部门计划的一部分，哥伦比亚大学的托尼·海因茨（Tony Heinz）将与来自其他几个工业和政府实验室的同事一起，利用光电技术探测表面和薄膜中分子和声子的远红外光谱区激发。这些研究人员将开发和改进相干远红外光谱来研究表面和界面问题，并将这项技术应用于迄今为止难以处理的表面和薄膜的广泛测量。多重反射和新的波导几何形状将提高该技术对表面和薄膜的灵敏度，和频产生方案将混合宽带远红外辐射和光谱狭窄的可见波长激光脉冲。超快时间分辨测量也将在若干研究中得到利用。要研究的材料系统包括聚合物薄膜、铁电薄膜和边缘金属中的离子掺杂剂。表面和薄膜涉及的材料数量有限，研究这些系统的方法通常不够灵敏。这项研究计划将导致使用新的光电方法测量这种凝聚态系统表面的极低能量激发的新技术。将审查具有重大技术相关性和重要性的材料和问题的广泛横截面。

In this project, part of the Cross-Directorate program for Multidisciplinary Research in Optical Science and Engineering, Tony Heinz at Columbia University together with colleagues from several other industrial and government laboratories will use optoelectronic techniques to probe in the far-infrared spectral region excitations of molecules and phonons in surfaces and thin films. These researchers will develop and refine coherent far infrared spectroscopy to study surface and interface problems and will apply this technique to a wide range of hitherto intractable measurements of surfaces and thin films. Multiple reflection and new waveguide geometries will enhance the sensitivity of the technique for surfaces and thin films, and sum-frequency generation schemes will mix broadband far infrared radiation with a spectrally narrow visible wavelength laser pulse. Ultrafast time-resolved measurements will also be exploited in several studies. Materials systems to be examined include ionic dopants in polymeric thin films, thin ferroelectric films, and marginal metals. Surfaces and thin films involve a limited quantity of material, and methods sensitive enough to study these systems are usually inadequate. This research program will lead to new techniques for measuring very low energy excitations at the surfaces of such condensed matter systems using novel optoelectronic methods. A broad cross section of materials and problems will be examined which have significant technological relevance and importance.