Spectral, magneto-optical and thermo-optical properties of terbium containing cubic zirconia crystal

Abstract

This letter presents the investigation of magneto-active media based on a cubic zirconia crystal. We studied spectral, magneto-optical and thermo-optical characteristics of a terbium containing cubic zirconia (TCZ) crystal aiming to estimate its applicability in magneto-optic applications. This crystal has significant advantages over the popular TGG crystal. The value of its Verdet constant for the radiation at the wavelength of 1075 nm is 31% higher than that of a TGG crystal. The value of the absorption coefficient is rather small and typical for commercially available TGG crystals. Its transmission spectrum is typical for terbium containing magneto-active media. The dispersion dependence of the Verdet constant had been measured for visible and near-IR ranges and presented in this paper. The optical anisotropy parameter which shows the distribution of orientations of the axes of thermally induced birefringence in a thermally loaded optical element had also been determined. Unlike a TGG crystal, the optical anisotropy parameter of a TCZ crystal is negative, which means that there exists a dedicated orientation of crystallographic axes, at which the axes of thermally induced birefringence are arranged in one direction and thermally induced depolarization may be reduced substantially. Such a combination of characteristics makes the TCZ crystal a very promising material for magneto-optical applications, for example, for creating Faraday isolators, including those with a high maximum permissible operating power.