TSAG-based Faraday isolator with depolarization compensation using a counterrotation scheme.

A Faraday isolator (FI) with depolarization compensation using a counterrotation scheme has been realized in experiment for the first time, to the best of our knowledge. It is based on terbium scandium aluminum garnet crystals with negative optical anisotropy parameters. An order of magnitude advantage over the traditional FI scheme is achieved in this case. An isolation ratio of 35.7 dB at a radiation power of 1440 W has been obtained. According to the numerical estimates, an isolation ratio of 30 dB can be provided up to a power of 5.5 kW.

Magneto-optical Faraday effect in dysprosium oxide (Dy2O3) based ceramics obtained by vacuum sintering.

The method of self-propagating high-temperature synthesis of submicron powders with subsequent vacuum sintering was used to produce a series of optical ceramics based on dysprosium oxide (DyxY0.95-xLa0.05)2O3, where x=0.7, 0.85, and 0.9. The influence of ceramics composition on optical transmission of the obtained samples was investigated. The studied materials had several transparency windows in the visible 500-730 nm, near-IR 1900-2300 nm, and mid-IR 3500-7500 nm ranges. The dependence of the Verdet constant on wavelength in the 400-1940 nm range was measured for each ceramics composition, and analytical approximations were obtained. When Y and La dopants were used, the Verdet constant depended linearly on the concentration of Dy3+ ions, and its value in the visible wavelength range was about twice that of the analogous value for a terbium gallium garnet crystal. The high transmission and relatively high Verdet constant make the produced materials highly promising for fabricating Faraday devices for Tm3+ and Ho3+ lasers and for lasers emitting in the visible spectrum.

TGG ceramics based Faraday isolator with external compensation of thermally induced depolarization.

A Faraday isolator with compensation of thermally induced depolarization outside magnetic field was implemented for the first time on TGG ceramics. Stable isolation ratio of 38 dB in steady-state regime at a laser power of 300 W was demonstrated in experiment. Theoretical estimates show a feasibility of a device that would provide an isolation ratio higher than 30 dB up to laser power of 2kW.