Sunday, March 11, 2007

Polarized Light Microscope is a microscope that utilizes polarized light to form a highly magnified image of an object. Polarizing microscopes play an important role in crystallography, petrography, microchemistry, and biology. Although all light microscopes compare poorly with electron microscopes with respect to image resolution, polarized light microscopes have the unique ability to deliver information about the submicroscopic structure of the objects being examined. They also have the advantage of being relatively nondestructive, and may be used safely with living cells. Polarized light microscopy positions two polarizing filters, called polarizers, in the light path. The polarizing filters are very similar to those found on polarizing sunglasses. Ideally, both polarizers will be rotatable. One polarizer is positioned before the sample, and the second (called the analyzer) is located between the back focal plane of the objective and the eyepieces (or camera). There are two traditional modes of use for the polarizing microscope, the orthoscopic mode and the conoscopic mode. In the orthoscopic mode, the ocular projects an image of the specimen, as in conventional microscopy. The conoscopic mode is used to characterize crystalline specimens.