Evanescent wave infrared spectroscopy of liquids using silver halide optical fibers

Abstract

Infrared spectroscopic measurements of liquids were performed in an attenuated total internal reflection cell, using infrared transparent silver halide fibers. As an example, we studied evanescent wave absorption in water. In particular, we analyzed absorption dependence on various physical parameters, such as the length of the absorbing medium and the geometry of the beam at the fiber entrance and exit faces. Absorption peaks were easily traced and experimental results correlated well with theoretical calculations. These studies may lead to practical uses of fiberoptic-based evanescent wave spectroscopy.