Author : Y.N.Ch.Ravibabu and S.V.G.V.A.Prasad

In this study, the principal role of Al2O3 on the physical properties and the features of the absorption spectra of Nd3+ ion doped 20PbO–20Bi2O3-(25-x)MgHPO4-24(25-x) B2O3–1Nd2O3-xAl2O3 (x=1, 2, 3 and 4 mol %) glass system has been investigated. The concentration of Al2O3 is varied from 1 to 4 mol% while that of Nd3+ is fixed. Oscillator strengths of hyper sensitive transitions have indicated that there is a gradual decrease in the asymmetry of the glass network with increase in the concentration of Al2O3 up to 4.0 mol%. The Judd–Ofelt theory was successfully applied to characterize Nd3+ spectra of all the three glasses. Based on the magnitude of the spectroscopic quality factor Ω4/Ω6, it appears that LBMBPNA1-4 glasses to be a kind of better optical glasses. From this theory various radiative properties, like transition probability A, branching ratio br and the radiative lifetime τR, for 2H11/2, 4F3/2, 4F9/2 and 4F5/2 levels in the spectra of these glasses have been evaluated. The values of life times for these levels show decreasing order as we increased the Al2O3 content. The reasons for such higher values have been discussed based on the relationship between the structural modifications taking place around the Nd3+ ions.

Keywords: Spectroscopic quality factor, radiative life time, J-O parameters, Polarizability, Al2O3 content, Polaron radius.

Article published in International Journal of Current  Engineering  and Technology, Vol.4,No.4 (Aug- 2014)