Structural and optical properties of Nd3+ in lithium fluoro-borate glass with relevant modifier oxides

Modifier oxides (MgO, CaO, CdO and PbO) based Nd3+ doped lithium fluoro-borate glasses were prepared by using the conventional melt quenching technique. The structural and optical properties of all lithium fluoro-borate glasses were characterized by means of X-ray diffraction and SEM analysis (structural), optical absorption, near infrared luminescence and lifetime decay measurements(optical). Broad XRD spectra and smooth surface of SEM image analysis reveals that these glasses have amorphous nature. Judd-Ofelt intensity parameters were calculated and used to explain the structural properties and to determine the radiative properties (radiative transition probabilities, branching ratios and radiative lifetimes) of efficient meta stable states. By pumping with diode laser excitation source at 805 nm, a broader NIR emission transition, F-4(3/2) -> I-4(11/2) was observed. This transition possesses large stimulated emission cross-section (sigma(p)) and branching ratio (beta) values. These values are compared with another Nd3+ doped glass. The decay froth the F-4(3/2) level is found to be bi-exponential. The F-4(3/2) level gives the highest quantum efficiency for all Nd3+ doped lithium fluoro-borate glasses. It indicates the efficient laser emission at 1.06 mu m. Crown Copyright (C) 2013 Published by Elsevier B.V. All rights reserved.