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Published on: May 27, 2018
Evanescent wave cavity-based spectroscopic techniques as probes of interfacial processes
Mathias Schnippering1, Simon R T Neil, Stuart R Mackenzie
1Department of Chemistry, University of Warwick, Gibbet Hill Road, Coventry, CV4 7AL, UK.
Chemical Society Reviews
|October 2, 2010
Summary
Evanescent wave cavity ring-down spectroscopy (EW-CRDS) offers high-time-resolution optical absorption measurements at interfaces. This surface-sensitive technique is powerful for studying interfacial processes, especially when combined with other methods.
Area of Science:
- Surface Science
- Spectroscopy
- Physical Chemistry
Background:
- Evanescent wave cavity ring-down spectroscopy (EW-CRDS) is a surface-sensitive optical absorption technique.
- It utilizes total internal reflection (TIR) to generate an evanescent field for probing interfacial properties.
- Current applications primarily focus on solid/liquid and solid/air interfaces.
Purpose of the Study:
- To introduce the fundamental principles of EW-CRDS.
- To discuss various EW-CRDS configurations, instrumentation, and design considerations.
- To highlight the technique's utility in studying interfacial processes with recent examples and future trends.
Main Methods:
- Coupling a pulsed or modulated laser beam into an optical cavity with at least one optical element (e.g., silica prism).
- Utilizing the evanescent field generated at the total internal reflection interface for optical absorption measurements.
- Combining EW-CRDS with electrochemical, microfluidic, or hydrodynamic techniques for enhanced interfacial analysis.
Main Results:
- Demonstrated EW-CRDS's capability for time-resolved optical absorption measurements at interfaces.
- Illustrated applications including molecular adsorption/desorption, nanostructure deposition/dissolution, and interfacial redox reactions.
- Introduced evanescent wave-broadband cavity enhanced absorption spectroscopy (EW-BB-CEAS) as a complementary technique.
Conclusions:
- EW-CRDS is a powerful tool for investigating interfacial properties and processes, particularly when integrated with other analytical methods.
- The technique shows promise for studying a range of interfacial phenomena, including those at the water-air interface.
- Future developments are expected to expand the application scope of EW-cavity based spectroscopy.
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