Spectroscopic properties of Pr3+ ions in cadmium borate glasses

Full text: The optical spectra of lanthanides in glasses are of much interest for many of the Ln3+ions exhibit potential laser transitions with glassy matrices providing optical homogeneity. A number of studies in the past decade have demonstrated that the optical properties can be tailored, within limits, by the choice of the glass network-forming and network-modifying ions. According to the Judd-Ofelt theory the spontaneous emission probabilities of forced electric dipole transitions of rare earth ions can be calculated from the absorption spectra, refractive index and density. The emission probabilities are also used to predict the other radiative properties like branching ratios, peak cross-sections and lifetimes. So we report here the results of our studies on optical absorption spectra of Pr3+ ions (1 mol%) doped in 49 CdCO3 + 50B2O3 (CB) and 10 RO + 39 CdCO3 + 50 B2O3 where R = Li, Na, K, Mg, Ca and Ba (RCB) glasses. Glasses of these compositions are prepared by mixing appropriate quantities of chemicals by melting at 1100 ± 50 deg C for 15 minutes. Each melt was then cast in a brass mould and thus obtained glass samples are annealed at 400 deg C for 12 hours. Absorption spectra for all samples are recorded between 400 - 650 nm 1250 - 2500 nm on a Jasco 7800 spectrophotometer and Shimadzu 3400 spectrophotometer respectively. Refractive indices for these glasses are measured using abbe refractometer with sodium light as source. The assigned energy level data of Pr3+ (4f2) in these glasses are analysed in terms of a parametrized model Hamiltonian and in turn satisfactory eigenvalues and eigenvectors for intensity analyses are obtained. Radiative properties for the fluorescent levels of Pr3+ : CB and RCB glasses are determined by using the Judd-Ofelt theory and these results are compared and discussed with similar results