Cavity Enhanced Spectroscopy: Applications Theory and Instrumentation
Environment: Trace Gas Monitoring
Published Online: 15 JUN 2011
Copyright © 2000 John Wiley & Sons, Ltd. All rights reserved.
Encyclopedia of Analytical Chemistry
How to Cite
Young, C. J., Washenfelder, R. A. and Brown, S. S. 2011. Cavity Enhanced Spectroscopy: Applications Theory and Instrumentation. Encyclopedia of Analytical Chemistry. .
- Published Online: 15 JUN 2011
Cavity-enhanced spectroscopy (CES) is a sensitive technique for measuring the absolute optical extinction by samples that absorb or scatter light. Like other spectroscopic measurements, CES is based on measuring the change in intensity of light as it passes through an absorbing medium, CES is unique because it employs very long effective path lengths that are achieved by using highly reflective mirrors to form a high-finesse optical cavity. A number of instrumental variations on this technique have been developed and successfully used to measure trace gas and aerosol concentrations in the atmosphere. CES is applicable to a wide range of atmospheric compounds with spectral absorptions. Detection limits vary with the application and molecule, but are typically of the order of parts per billion or parts per trillion in air.