Introduction to Polarized Light Microscopy

Polarized Light Microscopy:

Polarized light is a contrast-enhancing technique that improves image quality obtained from dichromatic materials compared to other techniques such as darkfield and brightfield illumination, differential interference contrast, phase contrast, Hoffmann modulation contrast, and fluorescence.

The sensitivity degree of polarized light microscopy is very high and can be used for both qualitative and quantitative studies focused on a wide range of anisotropic specimens. Qualitative polarizing microscopy is a very trending topic in today’s world, with a wide range of volumes dedicated to the subject.

In contrast, the quantitative aspects of polarized light microscopy, which are primarily employed in crystallography, represent a more difficult subject that is usually confined to geologists, mineralogists, and chemists.

Although, the advancement that had been done in the technologies from the past few years has helped biologists to study the birefringent character of many anisotropic sub-cellular assemblies.

It’s applications

The polarized light microscope is developed for the observation and to take photographs of the specimens that are visible primarily due to the optically anisotropic character.

To accomplish this task, the microscope must be equipped with a polarizer, located somewhere in the light path before the sample, and an analyser (a second polarizer), placed in the optical path between the objective rear aperture and the observation tubes have gone or camera port.

The contrast in the image takes place when the interaction of plane-polarized light with a birefringent (or double-refracting) specimen produces two individual wave components in which both are polarized in mutually perpendicular planes.

The velocities of these components, called normal and extraordinary wavefronts, vary and vary with the direction of propagation through the sample. After removing the specimen, the components of light as becoming out of phase, but then they are recombined with destructive and constructive interference when they are made to pass through the analyser. The laser beamsplitters which performs the optical polarizer optics takes advantage of convex mirrors optics.

Polarized light microscopy is able to provide information about absorption color and optical path boundaries between minerals of different refractive indices, similar to brightfield illumination, but the technique can also differentiate between isotropic and anisotropic substances.

In addition, the techniques of contrast-enhancing display the optical properties that are specified to anisotropy and disclose detailed information concerning the structure and composition of materials that do not hold any value for identification and diagnostic purposes.