Determination of magneto-optical quality and refractive index of bismuth germanium oxide single crystals grown by Czochralski technique

Bi12GeO20 single crystals were grown by the Czochralski technique. The critical diameter and the critical rate of rotation were calculated. Suitable polishing and etching solutions were determined. As a result of our experiments, the pale yellow and black single crystals were produced. The structure of the Bi12GeO20 has been investigated by X-ray diffraction, Raman and IR spectroscopy. The atomic ratio Bi/Ge was determined for the both crystals. The refractive indexes of both Bi12GeO20 crystals were determined by the spectroscopic ellipsometry method. Important properties of Bi12GeO20 for sensing applications, optical activity, Faraday rotation and absorption were measured and magneto optical quality was calculated and compared.

► The yellow and black Bi12GeO20 crystals were grown by the Czochralski technique.
► The structure of Bi12GeO20 has been investigated by XRD, Raman and IR spectroscopy.
► The refractive index was determined by the spectroscopic ellipsometry method.
► Magneto optical quality of yellow crystal is 10 times larger than black crystal.