The growth and defect structure of CdF2 and nonstoichiometric Cd1-x R (x) F2+x phases (R are rare earth elements or in): Part VI. The optical properties of Cd-0.9 R F-0.1(2.1) crystals

摘要

The optical properties of the isoconcentration series of Cd-0.9 R F-0.1(2.1) crystals (R = Y, La, Ce, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, or Lu) grown from a melt by the Bridgman method have been investigated. The crystals have an anomalous birefringence (similar to 10(-6)) nonuniformly distributed over the sample diameter; the dichroism in them does not exceed 10(-9). Scanning using a spectral modulator showed the nonuniform distribution of rare earth elements over the crystal diameter. The refractive indices n have been measured at wave-lengths of 0.436, 0.546, and 0.589 mu m. The character of change in n along the rare-earth series is nonuniform and similar to the change in n in Sr-0.9 R F-0.1(2.1) crystals. It is shown that the refractive indices in Cd1 - x R (x) F2 + x crystals, depending on the RF3 content, can be estimated using the method of molecular refraction additivity.