The theory and implementation of quantitative gas phase absorption measurements based on cavity-ringdown spectroscopy with pulsed lasers is discussed. The response of ringdown cavities is modeled using an eigenmode description of the electromagnetic field, and this general result is compared to a widely used intensity-based model of the response of ringdown cavities. These two approaches are shown to be equivalent in the limit of very long-cavities. Experimental results for long and short ringdown cavities are presented and compared, and quantitative absorption measurements in these two limits demonstrated. Finally, it is shown that absolute, high resolution (10 MHZ) absorption lineshapes can be obtained using a relatively broadband pulsed laser (100 MHZ) and a short ringdown cavity.
Citation: Cavity-Ringdown Spectroscopy. An Ultratrace-Absorption Measurement Technique (ACS Symposium Series, Volume 720)
Publisher Info: American Chemical Society , Washington, DC
Pub Type: Books
cavity ringdown spectroscopy, spectroscopy