Terahertz response of gadolinium gallium garnet (GGG) and gadolinium scandium gallium garnet (SGGG)

Abstract

We report the magneto-optical response of Gadolinium Gallium Garnet (GGG) and Gadolinium Scandium Gallium Garnet (SGGG) at frequencies ranging from $300\mathrm{GHz}$ to $1\mathrm{THz}$, and determine the material response tensor. Within this frequency window, the materials exhibit nondispersive and low-loss optical responses. At low temperatures, significant THz Faraday rotations are found in the (S)GGG samples. Such strong gyroelectric response is likely associated with the high-spin paramagnetic state of the Gd${}^{3+}$ ions. A model of the material response tensor is determined, together with the Verdet and magneto-optic constants.

9 pages, 5 figures and 3 tables