Polarization rotators maneuver incident-linearly-polarized light about an optical axis. A polarization rotator is used to quickly and accurately modulate the polarization state of an incoming light beam. Linear polarization is a confinement of an electric field vector or magnetic field vector to a given plane along the direction of propagation. There are many types of polarization rotators. Examples include an optical rotator, Faraday rotator, and halfwave plate. An optical rotator is used to rotate an image about a given axis. A Faraday rotator is an optical device that rotates polarization of light due to the Faraday Effect. A halfwave plate is utilized in rotating a plane of polarization from a polarized laser to any other desired plane, especially if the laser is too large to rotate. Other polarization rotators are commonly available.

Functions

Polarization rotators function in a variety of ways. An antenna is used in the optical rotation process. Optical rotators are un-mounted as free components or mounted. Light entering an input surface of the rotator is subjected to a number of reflections, alternate reflections being total internal reflections and the intervening ones being mirror reflections. At least one of the surfaces bears a layered polarizing material arranged to impart a defined polarization effect as between light entering and exiting the optical rotator. A Faraday rotator is used in a high-power optical rotator and isolator with large aperture, circulators, switches, polarimeters, magneto-optic sensors, and high-power laser systems. Polarization isolators are set for horizontal input polarization. However, most models can be reset for vertical input merely by rotating each polarizer 90°.  Whether horizontally polarized or vertically polarized, the output plane of polarization will be at 45°. To obtain horizontal polarization, a halfwave plate is place in a beam with its fast (or slow) axis 45° to the vertical. A halfwave plate can also change left circularly polarized light into right circularly polarized light or vice versa. Polarization rotators are designed and manufactured to meet most industry specifications.

Applications

Polarization rotators are used in a variety of applications. A polarization rotator is used in research and product development, and is suited for optical switching, polarimetry, and image enhancement (microscopy). Polarization rotators are also utilized in the instrumentation and medical fields.