Isotropic Versus Anistropic Materials When Using the Polarized Light Microscope
The polarized light microscope has long helped researchers in the physical sciences uncover different facts about the materials that they worked with. Chemists can use the polarized light microscope in order to look at how certain materials respond to certain environmental and chemical stresses. Physicists can use the polarized light microscope in order to look at the configuration of certain materials, and how these materials might be used to strengthen or weaken other materials. Moreover, the polarized light microscope can be used to distinguish isotropic versus anistropic materials.
In order to understand the significance of polarized light, one has to understand that light travels in waves; light can also travel in the vertical or horizontal directions, more commonly described as the perpendicular or parallel directions, respectively. A polarized light microscope makes use of these two different directions: if the filters in a polarized light microscope are aligned, the user sees nothing.
The Polarizer Versus the Analyzer
The polarized light microscope appears much like any other light microscope: there is a path of light that goes through a specimen, and the light transmitted reaches the objectives. The objectives magnify the specimen, so that the person looking through the eyepieces can see a larger version of the specimen more clearly.
However, in addition to all these, the polarized light microscope has two main filters. The analyzer is positioned above the specimen, and it is aligned in the perpendicular direction, so that light passes through the filter perpendicularly. On the other hand, the polarizer is positioned below the specimen, and it is aligned in the parallel direction, so that light passes through the filter horizontally. When these two filters are directly in the path of light, the user sees nothing because all the light that is transmitted from the light source is scattered out in different directions.
However, when the filters are adjusted, and when they are oriented in slightly differing directions, light comes in at varying angles from the light source, through the filters, and into the objectives. These differing angles of light allow scientists to study a specimen from many different angles, and to see the different bumps, crests, and valleys of a specimen that would otherwise be difficult to distinguish in conventional light microscopy. When coupled to a rotating specimen stage, scientists can even the see different sides and angles of the specimen, making polarized light microscopy a versatile tool for the physical sciences.
Isotropic Versus Anisotropic Materials
Polarized light microscopy has many different uses. For instance, scientists can use it to study the properties of different materials, and to distinguish different materials from each other. Scientists studying fabrics can distinguish between natural and synthetic fabrics using a polarized light microscope. Scientists can also discover the presence of dangerous asbestos fibers if they examine building materials under a polarized light microscope.
Scientists can also use the polarized light microscope to distinguish between isotropic and anistropic materials. Isotropic materials are those materials that have a relatively uniform separation and arrangement of individual atoms, such as cubic or ordered crystals, liquids, and gases. Isotropic materials will have uniform light scattering properties no matter what direction the light comes from. They will have a single refractive index.
On the other hand, anistropic materials will have a non-uniform distribution of individual atoms, so that they scatter light in all directions, and from different angles of the material. Almost all the materials and minerals on the planet are anistropic in nature. Such anistropic materials can also split light into two parts; polarized light microscopy makes use of this split, and all these scattered light rays are gathered into the filters so that more information can be gathered about the specimen being studied.
When one understands how light can travel, one can easily decipher how the polarized light microscope can distinguish between isotropic and anistropic materials. Light will travel uniformly through isotropic materials, while anistropic materials will have light going in different directions and behaving differently while traveling through the material itself. This can be useful in many fields such as chemistry, physics, and engineering; isotropic solids tend to crack in predictable directions because of their molecular and atomic layout, while anistropic solids can fracture or crumble.
These are only a few ways by which the polarized light microscope can help differentiate isotropic versus anistropic materials. Such research can be of great interest and importance to building and bridge engineers, pharmacists, and even food scientists. As there are more advances in the physical sciences, researchers can better understand these materials and how the polarized light microscope can be further improved to serve even more uses in the future.
