Use of thin discs in Faraday isolators for high-average-power lasers

The possibility of development of a Faraday isolator consisting of several thin magnetooptical discs was investigated. An analytical and numerical analysis was performed taking into account the photoelastic effect, the temperature dependence of the Verdet constant, and the Fresnel reflections between the discs. The depolarisation ratio caused by thermal effects was shown to be much weaker in the disc geometry than in the rod geometry. The results obtained suggest that it is possible to make a Faraday isolator for laser radiation with a multikilowatt average output power.