Investigation of the Gyrotropy in the Spectral Region of the Absorption "Shoulder" of the Oxide Crystal Bi12SiO20

Abstract

This paper presents the research of the gyrotropy of a pure Bi$$_{12}$$SiO$$_{20}$$ (BSO) and doped Bi$$_{12}$$SiO$$_{20}$$:Al (BSO:Al) crystals in the spectral region of ``absorption shoulder'' using measurements of the spectra of the natural optical rotation, the magneto-optical rotation and the optical spectroscopy. It is shown that the difference in the absorption of the BSO and BSO:Al crystals is related to the presence of two types of defects in the crystals BSO:Al – impurities $$\rm Al_{Si}^{3+}$$ in $$\rm[Al_{Si}^{3+}O_4]$$ and $$\rm Bi_{Si}^{3+}$$ in $$\rm[Bi_{Si}^{3+}O_4]$$. A ``red-shift'' of the optical rotation spectrum of BSO:Al crystals has also been observed relative to the optical rotation spectrum of BSO crystals.