Abstract
One of the most effective means for studying the properties of matter nondestructively is to observe how photons interact with it; that is, by optical spectroscopy. The two most common techniques in the optical region are absorption and reflection spectroscopy. But many organic and inorganic materials, such as powders, amorphous compounds, smears, gels and oils, can not be readily studied by either of these two techniques. Methods involving diffuse or attenuated total reflectance permit the study of some of these materials, but they possess severe drawbacks.