Faraday rotator glass .

Magneto Optical Glass /Faraday rotator glass materials Tb-20, Tb-23 and Tb-26 are designed for laser light flux output control in the magnetic field in visible and near-IR spectral range. It is used in manufacture of faraday rotating components based on Faraday rotation of the light polarization plane, such as optical isolators,circulators, magneto-optical modulators, fast optical switches, interleavers, laser gyroscopes, goniometric devices, magneto-optic storage and optical information process system, current measuring transducers for magnetic field measuring and high-voltage transmission line, new generation current sensors, wave guides, astrology, spaceflight control, satellite survey and other functional devices.
In high power laser systems, optical isolators are necessary to prevent the destruction of laser disks or other optical components caused by reflected laser from target. Faraday Isolators are passive unidirectional, non reciprocal devices that utilize the phenomenon of Magneto-Optic Rotation to isolate the source from reflections in an optical system. The isolator protects the laser oscillator from optical feedback making Faraday Isolators a key component in many of today's laser systems.
Large aperture Faraday rotator glass with high Verdet constant (defined as the rotation per unit path per unit field strength) is used as rotator material to obtain large rotation angle of linearly polarized laser form the given length of glass at low intensity of magnetic field.