High Verdet constant of Te20As30Se50 glass in the mid-infrared

Faraday isolator based on crystalline silicon for 2-µm laser radiation

The magneto-optical properties of single-crystal silicon were investigated as a function of wavelength and temperature. A bulk free-space traditional Faraday isolator for the radiation with a wavelength of 1940 nm (magnetic field ∼2.8 Т) was implemented. The negative value of the piezo-optical anisotropy ratio of the used material allowed for the development of a Faraday isolator with compensation of thermally induced depolarization without a reciprocal rotator. The potential of single-crystal silicon as a magneto-optical material for Faraday isolators operating at room as well as at cryogenic temperatures in high-power laser radiation was considered. It was shown that single-crystal silicon is highly promising for the development of Faraday devices, including ones for next-generation laser interferometers aimed at detecting gravitational waves.

Faraday Rotation of Dy2O3, CeF3 and Y3Fe5O12 at the Mid-Infrared Wavelengths

The relatively narrow choice of magneto-active materials that could be used to construct Faraday devices (such as rotators or isolators) for the mid-infrared wavelengths arguably represents a pressing issue that is currently limiting the development of the mid-infrared lasers. Furthermore, the knowledge of the magneto-optical properties of the yet-reported mid-infrared magneto-active materials is usually restricted to a single wavelength only. To address this issue, we have dedicated this work to a comprehensive investigation of the magneto-optical properties of both the emerging (Dy2O3 ceramics and CeF3 crystal) and established (Y3Fe5O12 crystal) mid-infrared magneto-active materials. A broadband radiation source was used in a combination with an advanced polarization-stepping method, enabling an in-depth analysis of the wavelength dependence of the investigated materials' Faraday rotation. We were able to derive approximate models for the examined dependence, which, as we believe, may be conveniently used for designing the needed mid-infrared Faraday devices for lasers with the emission wavelengths in the 2-μm spectral region. In the case of Y3Fe5O12 crystal, the derived model may be used as a rough approximation of the material's saturated Faraday rotation even beyond the 2-μm wavelengths.