• A polarizer is an optical filter that passes light of a specific polarization and blocks waves of other polarizations.
• It can convert a beam of light of undefined or mixed polarization into a beam with well-defined polarization.
• The common types of polarizers are linear polarizers and circular polarizers.
• Polarizers are used in many optical techniques and instruments, and polarizing filters find applications in photography and liquid crystal display technology.
• Polarizers can also be made for other types of electromagnetic waves besides light, such as radio waves, microwaves, and X-rays.