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

• Main Authors: C. R. Kesavulu, H. J. Kim, S. W. Lee, J. Kaewkhao, N. Wantana, E. Kaewnuam, S. Kothan, S. Kaewjaeng
• Format: Journal
• Published: 2018
• Subjects: Materials Science; Agricultural and Biological Sciences
• Online Access: https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=84994692144&origin=inward; http://cmuir.cmu.ac.th/jspui/handle/6653943832/46889
• 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 (1.39ï¿½× 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.