Polarization is a property of transverse waves that specifies the geometrical orientation of the oscillations. In a transverse wave, the direction of the oscillation is perpendicular to the direction of motion of the wave). Light waves are transverse waves, and polarization is an important parameter in areas of science dealing with transverse waves, such as optics, seismology, radio, and microwaves). Polarized light waves are light waves in which the vibrations occur in a single plane. The process of transforming unpolarized light into polarized light is known as polarization. There are a variety of methods of polarizing light, including:

• Polarization by use of a Polaroid filter: This is often demonstrated in a physics class through a variety of demonstrations. Filters are used to look through and view objects. The filter does not distort the shape or dimensions of the object; it merely serves to produce a dimmer image of the object since one-half of the light is blocked as it passed through the filter.

• Polarization by reflection off of nonmetallic surfaces: Unpolarized light can undergo polarization by reflection off of nonmetallic surfaces. The extent to which polarization occurs is dependent upon the angle at which the light approaches the surface and upon the material that the surface is made of.

• Polarization by refraction of light: Refraction occurs when a beam of light passes from one material into another material. At the surface of the two materials, the path of the beam changes its direction. The refracted beam acquires some degree of polarization.

• Polarization by scattering: Scattering occurs when light interacts with matter and is redirected in many different directions. The scattered light can become polarized.

Polarization is useful in many aspects of optical microscopy, and the microscope configuration uses crossed polarizers where the first polarizer is placed below the sample in the light. Polarization is also used in sunglasses to reduce glare.