Optical absorption and fluorescence spectral studies of Sm3+ ion in BaO-M2O3 (M = Ga, Al, In)-P2O5 glass systems

Abstract

BaO-P2O5 glasses mixed with three IIIA group metal oxides viz., Al2O3, Ga2O3 and In2O3 doped with Sm2O3 were prepared. Optical absorption and photoluminescence spectra of these glasses have been studied. The absorption spectra of these glasses have revealed the absorption bands due to 6H5/2 → 4I11/2, 4I13/2, 4G9/2, 6P5/2, 4F7/2, 6P7/2, 4D5/2, 4K17/2 transitions. By performing least square fit analysis, the Judd-Ofelt intensity parameters Ωλ for these glasses were evaluated; these parameters have exhibited the following trend: Ω2 > Ω4 >Ω6. The photoluminescence spectra with the excitation wavelength 400 nm recorded at room temperature of these glasses have exhibited the following emission transitions: 4G5/2 → 6H5/2, 6H7/2, 6H9/2. From luminescence spectra, various radiative properties like transition probability A, branching ratio βr, the radiative lifetime τr and the emission cross-section σE for various emission levels of these glasses have been determined and reported. Out of the three J-O parameters (Ωλ), the value of Ω2 which is related to the structural changes in the vicinity of the Sm3+ ion indicated the highest covalent environment of Sm3+ ion in indium mixed glasses. The luminescence spectra of all the three glasses suggested the highest of values of transition probability 4G4 → 6H9/2 in BGPSm glasses. The analysis of these results further indicted comparatively high non-radiative losses in In2O3 mixed glasses.