OPTICAL ISOLATOR WITH COMPENSATION FOR THERMALLY INDUCED DEPOLARISATION FOR HIGH-POWER LASERS Russian patent published in 2012 - IPC G02F1/09 G02B5/30 

FIELD: physics.

SUBSTANCE: optical isolator has, arranged in series on an optical axis, a polariser, a magnetooptic rotator installed in a magnetic system and an analyser. The magnetooptic rotator is in form of Faraday elements which rotate the polarisation plane by 22.5° each, between which there is a mutual polarisation rotator which rotate the radiation polarisation plane by an angle φ. Both Faraday elements are made from the same monocrystal with orientation [001], but have different directions of crystal axes θ₁ and θ₂ relative polarisation of radiation incident on the optical isolator, wherein the turning angle of the polarisation plane φ in the mutual polarisation rotator lies in the range from 70° to 74°. The ratio of the length of the Faraday elements varies from 0.96 to 1 and their specific values are defined by the optical anisotropy parameter ξ of the material from which they are made. The direction of crystal axes θ₁ and θ₂ of the Faraday elements relative polarisation of laser radiation is selected based on the condition of maximum degree of isolation of the optical isolator.

EFFECT: increase in the maximum allowable mean power of laser radiation and high degree of isolation.

2 cl, 1 dwg