Evanescent Wave Cavity Ring-Down Spectroscopy: A New Platform for Thin-Film Chemical Sensors

摘要

A new optical technique is described that permits extension of cavity ring-down spectroscopy (CRDS) to surfaces, films, and liquids. As in conventional CRDS, the photon intensity decay time in a low loss optical cavity is utilized to probe optical absorption. Extension to condensed matter is achieved by employing intra-cavity total internal reflection (TIR) to generate an evanscent wave that is especially well suited for thin film chemical sensing.