Polarizing Microscopes

Polarizing microscopes are a type of compound or light microscope often called petrographic microscopes or commonly know as PLM or Polarizing Light Microscopes since their main application is in studying the optical and chemical properties of rocks and minerals (mineralogy) under polarized light. This facilitates for the viewing under the microscope thin sections of slides the study of birefringent materials such as crystals and strained non-crystalline substances.

In a classic optical microscope, also known as the simple "light" microscope, visible light is sent through a series of lenses to magnify a sample. A polarizing microscope, or PLM, is an optical microscope with the addition of a polarizing filters that acts to polarize visible light.

According to the wave model of light, visible light is composed of two waves vibrating at right angles to each other along the direction the light is traveling. In other words, regular light vibrates in all directions. When light is polarized, it is forced to vibrate in one direction. Technically, polarizers convert circularly polarized light to linearly polarized light.

After light is polarized, it moves only in one direction. This is called linear polarization

The polarized light microscope (PLM) is designed to observe and photograph specimens that are visible primarily due to their optically anisotropic character.

Polarizing Microscopes (PLM) uses two filters; a polarizer, positioned in the light path somewhere before the specimen ( usually fixed to a left-right, or East-West position ) and an analyzer (a second polarizer), placed in the optical pathway between the objective rear aperture and the observation tubes or camera port.) and an analyzer (a second polarizer), set to a North-South position, though it can be rotated on some microscope models. The analyzer can be slid in and out of the path of the source light. The professional grades are equipped with Bertrand Lens system,compensator plates: quartz wedge, mica (1/4 wavelength), and gypsum (full wavelength) part of the analyzer.

Polarizer

Analyzer: situated on top of microscope - (under head and above objectives) Compliments of Meiji Techno

Using the polarizer by itself will assist in studying the sample under polarized light, while using both filters (polarizer and analyzer) allow study under cross-polarized light. While no light can pass under cross-polarized light, it is possible to discern mineral characteristics. Minerals within a sample are generally aligned at various angles, so as one rotates the stage, different parts will "black out" at different times. Cross polarization can be obtained by turning the polarizer and the analyzer at 90 degrees to each other, which is the extinction angle. At this extinction angle, most light transmission is blocked by the polarized filters. A polarized light microscope set at the extinction angle is able to view thin sections of birefringent specimens and see stunning coloration.

Polarizing microscopes are used for medical (Rhuematology) and industrial applications such as in viewing microscopic crystals in urine (gout); detecting defects in semiconductors or finding stress points in metal and glass; geology - studying meteorite thin specimens; biochemistry, biomedical research and petroleum or oil industry (mud logging) - such as studying fibers suspended in liquid or analyzing content and chemical makeup of many different organic and inorganic materials.

We carry quality brands of Polarizing Microscopes including Meiji (made in Japan) and Steindorff our own exclusive line. Please view the Polarizing Microscope Section for a complete listing offering many top quality manufactures that will satisfy most applications while meeting any budget without sacrificing quality. Also, please feel free to contact us directly for any personal assistance required @ 1 877 877 7274.