Faraday Crystal

With the laser technology being actively developed and the average power of both continuous wave and repetitively pulsed lasers steadily growing, the problem of reducing thermal effects occurring in various optical elements due to light absorption is becoming ever more important. A Faraday isolator (FI) is one of the optical devices that are most influenced by thermal self-action because of the relatively strong absorption (~10^-3 cm^-1) in the magneto-optical elements (MOEs). The nonuniform temperature distribution induced by absorption gives rise to linear birefringence (photoelastic effect), in addition to the Faraday effect, and transmitted beam wavefront distortions (thermal lensing). In high-power lasers the degree of isolation is limited by the thermally induced depolarization.

A Faraday isolator (FI) is a key optical component of many laser systems as it is used to prevent backward reflection from the laser-irradiated materials or forward optics. This device is important for laser-driven applications that utilize recently developed high-power lasers, such as high-energy and high-repetition lasers, ultra-high-power CW laser systems , and high-intensity laser systems.