A polarizing microscope is a special kind of microscope that utilizes two polarizing lens to acquire certain optical data from the specimen. The polarizing microscope is used extensively in the field of optical mineralogy which supports such applications as geology, asbestos testing, and forensic science. Often those working in different fields will sometimes refer to the polarizing microscope by different names such as geology microscope, petrographic microscope, pol microscope, and PLM (polarized light microscope.)
The key difference between the polarizing microscope and a standard compound microscope is the addition of a fixed polarizer between the light source and the specimen and the addition of an adjustable polarizer between the objective and the eyepieces. The 2nd polarizer is called the "analyzer" and usually can insert in and out on a rotating piece in the neck of the microscope. Other common accessories include a rotating stage and insertable retardation plates made from gypsum or quartz.
With these additional elements, the this microscope can acquire optical data from a specimen that no other microscope can. The key optical information available includes refractive index, birefringence, sign of elongation, pleochroism, and angle of extinction, all of which provide clues to the crystallography of the material that is being investigated.
The first uses of these kinds of microscopes over one hundred years ago was the identification of minerals in geology. In addition, the most common form of lab analysis to test for asbestos is performed with a polarizing microscope. Because of the their ability to provide optical data, these kind of microscopes are very commonly used in forensic science where the identification of unknown materials is a routine part of the job. Some of the first evidence disputing the claimed age of the so-called "Shroud of Turin" was determined by analysis of pigments using a polarized light microscope.
The polarizing microscope is a very versatile and powerful instrument in the identification of materials. It is a key tool in several scientific fields, and can sometimes be the best option over more expensive technologies. For example, in routine asbestos analysis the polarizing microscope was determined to be more accurate and much more cost effective than the other high-tech options that were first investigated, such as x-ray diffraction and scanning electron microscopy. It is a powerful tool with many applications.
A polarizing microscope is a special kind of microscope that utilizes two polarizing lens to acquire certain optical data from the specimen. The polarizing microscope is used extensively in the field of optical mineralogy which supports such applications as geology, asbestos testing, and forensic science. Often those working in different fields will sometimes refer to the polarizing microscope by different names such as geology microscope, petrographic microscope, pol microscope, and PLM (polarized light microscope.)