Understanding Polarized Light Microscopy
Polarized light microscopy must be the most underrated of all optic light microscopy techniques. In fact, it is a little better than the traditional bright field microscopy that is being in so many microscopes today. Polarized light microscopy is able to provide a number of observation tools that may be absent in any other principles of microscopy.
A polarized light microscope is a rather complex microscope. It is the one commonly used in petrography and it s applications. Petrography refers to the examination of minerals usually found in rocks, sediments, and precious stones. Geologists primarily use petrographic microscopes in their aim to understand more about the rock samples they have obtained in a particular area.
Perhaps the notable feature of a polarized light microscope that is not present in a regular bright field microscope is its ability to distinguish isotrophic materials from anisotropic materials. This microscope can also provide adequate information about the boundaries and color absorption between materials of varied refractive indices. This ability, however, is observable with a bright field microscope as well. It is just worth repeating because this is what a polarized light microscope normally does.
Polarized light microscope aims to reveal more detailed information of the structure and composition of minerals and anisotropic elements. And this is possible with the use of the necessary optical properties the microsocpe is capable of, which will eventually lead to the discovery and the identification of the sample.
Examples of isotropic materials are liquids, gases, cubic crystals, and unstressed glasses. All of these materials are known to demonstrate similar optical properties in any direction. All of them have single refractive index. They also have no restrictions on the course of the vibration of the light the passes through them.
On the other hand, anisotropic materials are usually dense, solid substances. As such, they have optical characteristics that differ depending upon the direction of the incident light in accordance to crystallographic axes. Anistropic materials work like beam splitters. They divide the light rays passing through them into two parts. The polarized microscopy technique capitalizes on the interference as produced by rays of the split light. That split light will be reunited somewhere along the identical optical path. And this feat is what actually allows for the extraction of information about the materials being observed.
As implied earlier, polarized light microscopy is primarily used for geological applications. It is the type of microscope employed when thin rock sections are the samples to be studied. But of course, the use of these microscopes is not limited to those materials alone. Polarized light microscopy can certainly be used with other materials as well. Polarized light microscopes is also perfect for industrial materials occurring naturally or otherwise, including refined, manufactured, or extracted composites like ceramics, cements, polymers, mineral fibers, and crystalline.
But aside from geological and industrial applications, polarized light microscopy can also be used in the field of biology. Right now, it is used to inspect human and animal DNA. Accordingly, it can be useful in analyzing urea, starch, and wood. And generally speaking, this microscope is a perfect candidate for all measuring tasks, whether qualitatively or quantitatively. It is an excellent tool for chemistry, metallurgy, and materials science, as well as medicine.
Polarized light microscopes are equipped with two important parts - the polarizer and the analyzer. These two filters work hand in hand to produce the illumination and imaging effect required when applying the microscopy technique. A rather complex structure of light travel sequence is involved in the whole process. But then again, it all leads down to the fact that mineral specimens are specifically observed with full clarity and detail under the probing lenses of a polarized light microscope.
Polarized light microscopes can use both transmitted and reflected light when illuminating its sample. Reflected light is commonly used for opaque materials like metals, sulfides, silicon wafers, metals, and mineral oxides.
The practical applications of polarized light microscopy includes the classification of asbestos fiber, determining the history of a certain rock formation, analysis of both natural-occurring and synthetic polymers, and observation of nylon fibers, among others. And there certainly are several other minor applications of polarized light microscopes today.
Polarized light microscopy is the same technique followed by petrographic microscopes. And right now, there are quite a number of them available in the market. To get a deeper understanding of petrographic microscopes and their applications, check out petrographic-microscope.com. The site is the information authority when it comes to petrography and petrographic microscopes.
