Spectroscopic investigations of Nd³⁺doped gadolinium calcium silica borate glasses for the NIR emission at 1059 nm

• Main Authors: Kesavulu C., Kim H., Lee S., Kaewkhao J., Wantana N., Kaewnuam E., Kothan S., Kaewjaeng S.
• Format: Journal
• Published: 2017
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84994692144&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/41084
• Institution: Chiang Mai University

© 2016 Elsevier B.V. The Nd 3+ -doped gadolinium calcium silica borate (BSGdCaNd) glasses of composition (55-x) B 2 O 3 - 10 SiO 2 - 25 Gd 2 O 3 -10 CaO -x Nd 2 O 3 , where x = 0.0, 0.05, 0.5, 1.0, 1.5, 2.0 and 2.5 mol %, have been prepared by conventional melt quenching technique and are characterized through structural, thermal, absorption, emission and decay time measurements. Based on the Judd-Ofelt intensity parameters and radiative properties were determined from the absorption spectrum. The emission spectra recorded for BSGdCaNd glasses gives three emission transitions 4 F 3/2 → 4 I 9/2 (903 nm), 4 F 3/2 → 4 I 11/2 (1059 nm) and 4 F 3/2 → 4 I 13/2 (1334 nm) for which effective bandwidths (Δλ eff ) and stimulated emission cross-section (σ(λp)) are evaluated. Branching ratios (β R ) measured for BSGdCaNd0.5 glass show that 4 F 3/2 → 4 I 11/2 transition is quite suitable for lasing applications. The intensity of emission spectra increases with increase in the concentration of Nd 3+ ion up to 1.0 mol% and beyond that concentration, quenching is observed. The decay from 4 F 3/2 level is found to be non-exponential nature for concentrations of Nd 3+ ions. The non-exponential curve has been fitted to the Inokuti-Hirayama model to understand the nature of energy transfer process. Hence, the high emission cross-section (1.39 × 10 −20 cm 2 ), branching ratio (0.58) and long lifetime (342 μs) indicate that the BSGdCaNd0.5 glass system could be considered as a good candidate for strong NIR lasers at 1059 nm.