Spectroscopic investigations of neodymium doped barium bismuth fluoroborate glasses K. Mariselvam a , R. Arun Kumar a,b,⇑ , P. Manasa c a GRD Centre for Materials Research, PSG College of Technology, Coimbatore 641 004, India b Department of Physics, PSG College of Technology, Coimbatore 641 004, India c Department of Physics, Sri Venkateswara University, Tirupati 517 502, India highlights  Concentration dependent luminescence behavior of the title glasses was studied.  Lower Urbach’s energy values indicate that, the studied glasses possess minimal defects.  Higher 2 values indicate the higher asymmetry around the RE ions site in the prepared glasses.  Higher (r E P ) and b values of BBFBNd0.5 glass is suggested for suitable infrared applications. article info Article history: Received 14 November 2017 Revised 13 March 2018 Accepted 23 March 2018 Available online 3 April 2018 Keywords: Amorphous material Nd 3+ : glasses Urbach energy Photoluminescence Judd-Ofelt parameter Infrared laser abstract A new series of neodymium doped barium bismuth fluoroborate glasses with the chemical composition of (70-x)H 3 BO 3 + 5Bi 2 O 3 + 10BaCO 3 + 7.5CaF 2 + 7.5ZnO + xNd 2 O 3 (where x = 0.05, 0.1, 0.25, 0.5, 1, 2 (in wt. %) have been prepared by the conventional melt quenching method. The powder X-ray diffraction pattern confirms the amorphous nature of the prepared glasses. The Urbach energy reveals the minimum disor- derness of the glass samples. Judd-Ofelt intensity parameters (X k = 2, 4 and 6) were derived from the absorption spectrum and were used to calculate the emission properties. The near infrared emission spectra recorded with 808 nm laser diode excitation for different concentrations of Nd 3+ ions and the emission for the 4 F 3/2 ? 4 I 11/2 transition at 1060 nm found to be high intense. The measured decay curves for 4 F 3/2 fluorescent level exhibit single exponential nature with shortening of lifetime with increase in concentration. The laser parameters such as stimulated emission cross-section, branching ratios, gain band width and optical gain values are found to be high for BBFB:Nd 3+ (0.5 wt%) glass. Hence, the results suggested that the present BBFB:Nd 3+ (0.5 wt%) glass could be used as an efficient infrared laser source around 1.06 lm region. Ó 2018 Published by Elsevier B.V. 1. Introduction Suitable rare earth ions doped in an optimized host glass matrix can luminance in the visible and infrared regions. These materials have luminescence properties due to 4f-4f and 4f-5d electronic transitions of the rare earth ions. The 4f-4f transition emits sharp emission from UV to infrared region which are highly useful for developing solid state lasers, optical detectors, solar concentrators, waveguide lasers, optical fibers and display devices. Oxide glasses are very suitable and stable hosts for doping with rare earth ions to obtain efficient luminescence. Borate glasses are good optical materials possessing low melt- ing points, high transparency, high thermal stability and suitable rare earth ion solubility [1]. The addition of barium carbonate to a system enhances thermal stability, optical and mechanical prop- erties of the glasses. The addition of fluoride compounds increases the broad emission and lifetime of the glasses compared to the pure oxides [2]. The inorganic compounds containing bismuth cation as a host show its original luminescence from 6S6P ? 6S 2 transition. Bismuth oxide (Bi 2 O 3 ) has high polarizability, low field strength and being in higher valency oxide state affects its own glass forming ability. However, in the presence of a glass former like boron trioxide, the bismuth ions will occupy both network forming and network modifying positions [3]. These compounds ensure its high effective recording of ionizing radiation, X-ray and gamma ray detection due to its high density and high effective https://doi.org/10.1016/j.infrared.2018.03.021 1350-4495/Ó 2018 Published by Elsevier B.V. ⇑ Corresponding author at: GRD Centre for Materials Research, PSG College of Technology, Coimbatore 641 004, India. E-mail address: rak@phy.psgtech.ac.in (R. Arun Kumar). Infrared Physics & Technology 91 (2018) 18–26 Contents lists available at ScienceDirect Infrared Physics & Technology journal homepage: www.elsevier.com/locate/infrared