Abstract

Cavity ring-down spectroscopy (CRDS) is a new technique for carrying out absorption measurements with increased sensitivity. Briefly, a pulse of radiation is injected into an optical cavity where it bounces back and forth between high-reflectivity mirrors. Some radiation leaks out an end mirror on each bounce, and the stored radiant energy inside the optical cavity decays exponentially (rings down) with time. When absorber molecules are present inside the optical cavity, the ring-down lifetime is shortened. A plot of the reciprocal of the ring-down lifetime (the ring-down rate) versus frequency gives the absorption spectrum.

© 2002 Optical Society of America