Evanescent wave cavity-based spectroscopic techniques as probes of interfacial processes.
Evanescent wave cavity-based spectroscopic techniques as probes of interfacial processes.
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DOI：
10.1039/c0cs00017e
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发表时间：
2011
影响因子：
46.2
通讯作者：
Mathias Schnippering;Simon R. T. Neil;S. Mackenzie;P. Unwin
中科院分区：
文献类型：
--
作者：
Mathias Schnippering;Simon R. T. Neil;S. Mackenzie;P. Unwin
倏逝波腔衰荡光谱（EW-CRDS）是一种表面敏感技术，它可以测量界面处的光吸收，具有良好的时间分辨率。在EW-CRDS中，脉冲或调制的激光束被耦合到光学腔中，该光学腔由至少一个光学元件（例如二氧化硅棱镜）组成，在该光学元件的表面处，光束经历全内反射（TIR）。在TIR的位置处，建立了渐逝场，其幅度随着离边界的距离而指数衰减。这种倏逝场可以用来研究界面性质和过程，如吸附和表面反应，迄今为止大多数应用集中在固/液和固/气界面。如本文所强调的，EW-CRDS与其他技术（如基本电化学测量和微流体或流体动力学技术）相结合时，对于界面过程的研究特别强大。在本教程回顾中，将介绍EW-CRDS的基本要素，并讨论EW-CRDS不同配置的相对优点，沿着仪表和设计的各个方面。使用EW-CRDS可以获得的信息的类型示出了最近的例子，如分子吸附/解吸，沉积/溶解的纳米结构和界面氧化还原反应的重点。介绍了一种新的、互补的EW-宽带腔增强吸收光谱技术（EW-BB-CEAS），并讨论了它与EW-CRDS相比的优点。最后，展望了EW腔基光谱学的未来发展和趋势。值得注意的是，扩展的技术，以探测其他接口的潜力举例说明了在水-空气界面的初始界面吸光度测量的讨论。
Evanescent wave cavity ring-down spectroscopy (EW-CRDS) is a surface sensitive technique, which allows optical absorption measurements at interfaces with good time resolution. In EW-CRDS, a pulsed or modulated laser beam is coupled into an optical cavity which consists of at least one optical element, such as a silica prism, at the surface of which the beam undergoes total internal reflection (TIR). At the position of TIR, an evanescent field is established whose amplitude decays exponentially with distance from the boundary. This evanescent field can be exploited to investigate interfacial properties and processes such as adsorption and surface reactions, with most applications hitherto focusing on solid/liquid and solid/air interfaces. As highlighted herein, EW-CRDS is particularly powerful for investigations of interfacial processes when combined with other techniques such as basic electrochemical measurements and microfluidic or hydrodynamic techniques. In this tutorial review, the basic elements of EW-CRDS will be introduced and the relative merits of different configurations for EW-CRDS discussed, along with various aspects of instrumentation and design. The type of information which may be obtained using EW-CRDS is illustrated with a focus on recent examples such as molecular adsorption/desorption, deposition/dissolution of nanostructures and interfacial redox reactions. The comparatively new, but complementary, cavity technique of EW-broadband cavity enhanced absorption spectroscopy (EW-BB-CEAS) is also introduced and its advantages compared with EW-CRDS are discussed. Finally, future developments and trends in EW-cavity based spectroscopy are predicted. Notably, the potential for extending the technique to probe other interfaces is exemplified with a discussion of initial interfacial absorbance measurements at a water-air interface.