Cavity ring-down spectroscopy and its applications to environmental, chemical and biomedical systems

Abstract

In recent times, the need for high-sensitive detection has grown drastically as more and more applications of molecular sensing are being explored. Cavity ring-down spectroscopy (CRDS) is one of the new age and robust techniques which has revolutionized the field of molecular detection, particularly gas-phase analysis. In this short review, we have first provided a brief introduction to the working principles and system requirements of CRDS. Subsequently, we have described the various applications of CRDS in detail, including environmental monitoring, biomedical analysis specifically human breath analysis and reaction chemistry. We have also focused on the importance of isotope analysis and their accurate measurements using CRDS and its variants. Furthermore, we described the use of CRDS in the condensed phase through evanescent wave (EW) coupled CRDS and discussed its applications in the investigation of interfacial kinetics, thin-film and biological detection. We also outlined certain variants of CRDS to give a glimpse of the different techniques which have emerged with CRDS. Hence, in this mini-review, we aimed to illustrate the use of the CRDS technique in various interdisciplinary fields. SYNOPSIS The review provides an overview of the cavity ring-down spectroscopy (CRDS) technique and its variants. The applications of CRDS in environmental monitoring, biomedical diagnostics, reaction chemistry and isotope analysis for both the gas phase and the condensed phase molecules have been discussed.