Polarized Light Microscopy
The polarized light microscope (PLM) is a particle analyst’s primary tool for particle classification and identification. The polarized light microscope can use a variety of objectives that result in magnifications from 25-1000 times and an ultimate resolution of just below 1 μm. Nearly every sample at Microtrace is examined by PLM, which can provide initial information about a sample. Many materials can be specifically identified on the basis of their appearance or optical characteristics alone. For other samples, particles can be characterized as organic or inorganic, anthropogenic or natural, crystalline or amorphous. For mixtures such as dusts or white powders, the homogeneity or heterogeneity of a sample and the number of components can be quickly ascertained. In other samples, such as pharmaceutical formulations or food ingredients, specific components or contaminants can be located, identified, sized, or characterized.
In addition to morphological identification, the PLM can be used to measure specific optical properties such as refractive indices, birefrengence or optic sign (to name a few). These properties can be used to identify a particle, or provide some quantitative measurement of the properties of a particular material. Coupled with other accessories, such as a mercury burner or a hot stage, the PLM can provide even more specific types of information.