Optical properties of Bi12SiO20 single crystals doped with 4d and 5d transition elements

Bi 12 SiO 20 single crystals doped with Ru, Rh, Pd, Re, Os, and Ir transition elements were obtained. Optical absorption and optical activity were measured in the visible spectral range. Strong changes were observed in transmission spectra when doping with various elements. Doping with Os and Pd causes strong bleaching to the crystals, changes the transmission curve shoulder, and decreases the absorption coefficient. Transmission spectra of Ru, Re, and Ir doped crystals are shifted to the red region and the absorption coefficient is considerably increased. Optical rotatory power remains unchanged by doping with Rh, Pd, Re, and Ir. It is increased negligibly by Pd doping, considerably increased by Os doping, and strongly decreased by Ru doping. The influence of doping elements on optical rotatory power is discussed on the basis of the two elementary structural unit cells (BiOn polyhedra and SiO4 tetrahedra) and of the transition energy of electrons located in their vicinity.