ABSTRACT
One of the most powerful microscopy techniques is also one of the simplest. Polarizing light microscopy (PLM), also called petrographic microscopy, was first used in geology for identification of minerals. Samples that interact with polarized light are crystalline or pseudocrystalline, meaning that some order appears within their structures. The degree of order is revealed by interference colors created by interactions of light with the material. Light may be polarized in several ways: linearly, circularly, and elliptically. Our discussion will focus on linear polarization. It is a good idea to return to Chapter 1 to review the concepts of vector and wave notation as we will make extensive use of these concepts in this chapter.
