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Cavity Enhanced Spectroscopy: Applications Theory and Instrumentation

Environment: Trace Gas Monitoring

  1. Cora J. Young1,2,
  2. Rebecca A. Washenfelder1,2,
  3. Steven S. Brown3

Published Online: 15 JUN 2011

DOI: 10.1002/9780470027318.a9195

Encyclopedia of Analytical Chemistry

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. .

Author Information

  1. 1

    NOAA Earth System Research Laboratory, Boulder, Colorado, USA

  2. 2

    University of Colorado, Boulder, Colorado, USA

  3. 3

    NOAA Earth System Research Laboratory, Boulder, Colorado, USA

Publication History

  1. Published Online: 15 JUN 2011

Abstract

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.