A Faraday rotator is a  non-reciprocal optical device which rotates the polarization plane of both forward and backward transmitted beam in a certain direction, regardless of the transmission direction of the beam. A Faraday rotator with 45ºpolarization rotation and a pair of polarizers

 (the two polarizers being crossed at 45ºto each other) constitute an optical isolator. Only the forward transmitted beam is able to pass through the optical isolator with very low attenuation while the backward beam is blocked. Using a pair of specially designed birefringent prisms to replace the uses   Glen prisms, the set becomes a polarization insensitive isolator, i.e. it works for any polarization state of the incident beam not just for a linear polarization in a special direction. This is more convenient and lower cost device.

   Faraday rotators and isolators are widely used in various laser systems such as laser diode pumped lasers, seed injection lasers,  (optical parameter oscillators), ring lasers , mufti-stage laser amplifier system, Er doped optical fiber amplifier systems etc. Faraday rotator and isolator are necessary in those system to avoid the harmful backward reflection which causes instability of the laser modes and even optical damage.

   Physcience has a complete product line of Faraday rotators and polarization insensitive isolators, with facilities for the growth, processing of the magneto-optical crystal Terbium Gallium Garnet (TGG), permanent magnet processing , assembling and testing. The special magnet design decreases the size of the products. The typical aperture of Physcience Faraday rotators and isolators is 5-100 mm in diameter, for wavelengths of 400-1100nm (excluding 480nm).