Farady Crystal

Terbium Gallium Garnet  (TGG) is the right crystal material for Farady devices (Rotator and  Isolator). The Farady rotator is made up of a TGG rod contained in a  special designed magnet. The polarization of a light beam passing  through the rotator makes rotation. The direction of rotation is only  dependent on the direction of the magnetic field and not on the  direction of propagation of the light beam. The optical isolator  consists of a 45 degree rotator set between two suitably arrayed  polarizers which allow a light beam to pass through in one direction  only. With a combination of excellent properties, such as large verdet  constant, low light loss, high thermal conductance and high light damage  threshold, TGG is the unique material for Farady devices. It is widely  used for YAG lasers and Ti:sapphire tunable lasers, ring lasers ,etc.