Abstract

The ability to detect and quantify small concentrations of trace gases is an important part of many fundamental and applied studies being conducted today. Such challenges are found in atmospheric sciences, medical diagnostics, industrial process control, plasma analysis, kinetical studies and fundamental spectroscopy. High demands are, therefore, imposed on analytic instrumentation. Since the absorption spectrum has a fingerprint characteristic for each molecule, spectroscopic methods allow specific detection of a broad range of substances. Over the past few years, active research has lead to improved techniques enabling to reach the ppb detection level. There is presently a strong interest in developing spectrometric instruments able to simultaneously provide a large spectral bandwidth of observation, a high sensitivity, a high spectral resolution and a rapid acquisition time. Most often, these recent techniques couple broadband light sources to path length enhancement schemes, such as cavity ring-down spectroscopy or intracavity laser absorption spectroscopy.

© 2007 IEEE