ABSTRACT
This chapter is devoted to a more sophisticated outline of the underlying theory starting with the basics of qualitative analysis and earlier work on evaluation of optical constants and some preliminary work on quantitative analysis of concentrations. When determining the concentration of a strong absorber in a multi-component system, one finds only attenuated reflection, and no longer total reflection due to absorption. As a result, it is suggested that this type of spectroscopy should be referred to as evanescent wave spectroscopy. The behavior of an electromagnetic wave that interacts with a piecewise homogeneous medium is described completely by Maxwell’s equations. The dashed lines, which are extrapolated from the initial slope of the curves, indicate the validity of a linear approximation.
