Concentration dependence of intensity parameters and radiative properties of Sm3+ ions doped in BaO–ZnO–B2O3 glasses

Abstract

Glass samples with compositions xSm2O3- (100−x)[0.1BaO–0.4ZnO–0.5B2O3]; x = 0.5, 1.0, 1.5 and 2.0 have been prepared using melt quench technique. Optical absorption and fluorescence spectra have been recorded for prepared glass samples at room temperature. The spectral intensities of Sm3+ transition observed in absorption spectra have been calculated by using Judd–Ofelt theory. The intensity parameters (Ω2, Ω4 and Ω6) have been estimated by applying least square fit method on the experimental (fexp) and calculated (fcal) oscillator strengths. The variation of Ω2 observed with the increase in Sm3+ ion concentration, is attributed to decease in covalency of rare earth oxygen bond due to change in optical basicity of host glass matrix. From the fluorescence spectra, four emission spectral lines have been observed that correspond to the transition from 4G5/2 ground state to lower lying 6H5/2, 6H7/2, 6H9/2 and 6H11/2 states with an excitation wavelength of 402 nm. The intensity parameters and the emission measurements have been used to estimate the various radiative parameters such as transition probabilities (AR), radiative lifetime (τR), branching ratio (βR) and stimulated emission cross-sections (σe) of luminescent levels. The value of σe is found to decrease with increase in concentration of Sm3+ ions and it possesses higher value for glass sample with x = 0.5 for transition lying in the visible region indicating its importance for photonic applications.