Faraday isolator with 2.5 tesla magnet field for high power lasers

Abstract

The inevitable thermal emission in magneto active elements is the basic fundamental problem limiting use of Faraday isolators (FIs) in high average power lasers. The non-uniform temperature distribution in magneto-optical medium at increase of laser power leads to depolarization due to photoelastic effect. Hence it leads to reduction of isolation ratio of FI and power of the laser beam passing through the FI cannot exceed limiting value P max at given isolation ratio. For commercial FIs, the typical magnitude is P max =100 W for the isolation ratio of 30 dB.