Abstract

Cavity ringdown (CRD) absorption spectroscopy with continuous-wave (cw) tunable coherent sources is recognised as a convenient, sensitive and precise way to measure very weak optical absorption spectra. We have recently introduced several innovations in CRD technique, with one or more single-mode tunable diode laser (TDL) sources, a rapidly swept ringdown cavity,¹ and a simple optical heterodyne detected (OHD) approach (based on the dynamics of coherent light reflected from such an active optical cavity)^2-4.

© 2002 Optical Society of America