Optical activity of doped sillenite crystals

Bi12Si12O20 (BSO), Bi12GeO20 (BGO), and Bi12TiO20 (BTO) crystals doped with Al, P, and V and co-doped with Al + P were prepareded. The optical activity of the materials produced was studied in the 480–1180 nm spectral range. As a result of the doping, large changes were observed near the absorption shoulder from 480 to 590 nm. It is established that in BSO, Al and V decrease the optical rotatory power about 6.2% and 7.9%, respectively, whereas P slightly increases it by about 0.4% at 480 nm. Co-doping with Al and P mutually compensates the influence of the other. In the BGO crystals, P decreases the optical rotatory power, in contrast to the case of BSO:P. In co-doped Al + P BGO, the optical rotatory power decreases in the short wavelength range by about 7.2%. It was found that in BTO, Al and P increase the optical activity to the same extent, approximately 5.5%. Co-doping with Al + P doubles the influence of both dopants (about 118.3% at 480 nm). Above 590 nm the change of the optical rotatory power due to the dopants is in the order of 1–2.5%.