Magnetoactive media for cryogenic Faraday isolators

We analyzed a number of optical media, such as GGG, Nd:YAG, Yb:YAG, fused silica, CaF2, Yb:CaF2, and CdMnTe, that have not been used, to our knowledge, in the cryogenic Faraday isolator (FI) before. The temperature dependence of the Verdet constant and thermo-optical constants was experimentally investigated for λ=1.07 μm. We calculated the magneto-optical figure-of-merit and assessed the feasibility of using FI media with multikilowatt average laser power.