When engineers, chemists and physicists discuss polarization, they could be talking about anything from the diffraction efficiency of a hologram to the precision of a micromachining laser to the brightness of an LCD system. With such diverse applications, it is critical to understand polarization and how it affects the project at hand.

Polarization is the direction in which the electric field of a light wave oscillates. Because lightwaves are transverse waves, the electric field is always perpendicular to the direction of the propagation of the beam (the Z-direction, for example). Plane-polarized or linearly polarized light is characterized by the electric field always remaining parallel to the X- or Y-direction, or to some angle in between. Light rays from the sun, a lightbulb or a candle flame are classified as unpolarized because the direction of polarization varies continuously and randomly...