Contents lists available at ScienceDirect Journal of Non-Crystalline Solids journal homepage: www.elsevier.com/locate/jnoncrysol Europium-doped boro-telluro-dolomite glasses for red laser applications: Basic insight into spectroscopic traits Ibrahim Bulus a,c , R. Hussin a , S.K. Ghoshal b, ⁎ , Abd Rahman Tamuri a , Ibrahim Mohammed Danmallam a,d , Yamusa Abdullahi Yamusa a,e a Phosphor Research Group, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia b Advanced Optical Materials Research Group & Laser Centre, Department of Physics, Faculty of Science, Universiti Teknologi Malaysia, 81310 Skudai, Johor, Malaysia c Department of Physics, School of Sciences, Kaduna State College of Education Gidan Waya, Kafanchan, Nigeria d Sokoto Energy Research Centre, Usmanu Danfodiyo University, Sokoto, Nigeria e Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Nigeria ARTICLE INFO Keywords: Boro-telluro-dolomite glasses Europium ions Optical band-gap energy Red emission Judd–ofelt analysis Radiative parameter ABSTRACT Naturally abundant minerals and lanthanide-doped synthetic boro-tellurite networks have become prospective efficient laser hosts because of the synergy between them. Driven by this idea, Eu 3+ -doped boro-telluro-dolomite (BTD) glasses were prepared via the melt-quenching method. The spectroscopic traits of as-quenched samples were analyzed though experimental and theoretical studies. The result from the derivation of absorption spectral fitting (DASF) model demonstrated the direct allowed transition in the glasses. Moreover, the photo- luminescence spectra of the sample containing 1.0 mol% of Eu 3+ (BTD1.0Eu glass) revealed a prominent red peak at 611 nm (assigned to 5 D 0 → 7 F 2 transition in Eu 3+ ion) with a large stimulated emission cross section ( × − 7.15 10 cm 22 2 ) and a high luminescence branching ratio (61.5%). Furthermore, the attained CIE color co- ordinates (0.637, 0.363), which lie near the standard red hue (0.67, 0.33), together with high quantum effi- ciency (92.7%) affirmed the effectiveness of BTD1.0Eu glass as a potential red laser host. 1. Introduction Recently, synthesis and characterizations of novel rare-earth ion- doped glasses have attracted renewed interests to achieve inexpensive and efficient solid-state laser materials suitable for eye-safe applications [1–7]. Generally, a potential laser glass host possesses a low phonon energy, wide optical band-gap energy (OBGE), high refractive index, and large stimulated emission cross-section (SEC) to produce long fluorescence lifetime and spontaneous emission at selective pumping [8, 9]. Interestingly, boro-tellurite (BT) glass matrix has been approved as an appropriate host for attaining the aforesaid goal because of its distinct properties, such as compromised phonon energy (700–800 cm -1 ), good chemical stability, high transparency in the mid-infrared region, and low melting point [10, 11]. Lima et al. [12] claimed that the presence of artificial calcium modifier in the BT (B 2 O 3 -TeO 2 ) network can appreciably enhance its chemical stability, non-hydroscopic character, and radiative response, which are beneficial for solid-state lasers and light-emitting devices. Karthikeyan et al. [13] further studied the luminescence of Dy 3+ -doped calcium boro-tellurite (CBT) glasses for white light emitter application. Recently, Queiroz et al. [14] reported the spectroscopic characteristics of Sm 3+ -doped calcium boro-tellurite (CBT) glasses. Indeed, the ex- ceptional luminescence performance and red-orange color exhibited by these glasses declared their candidateship for light-emitting diodes (LEDs) and tunable lasers. Despite this claim regarding CBT glasses, researchers have seldom used calcium-rich natural minerals as modi- fiers in BT glasses for potential applications. According to our expectations, an admixture of synthetic BT and dolomite mineral can form boro-telluro-dolomite (BTD) glasses of high quality. This was further validated by the work of Abdellaoui et al. [15] wherein the glass forming ability, mechanical, thermal, and optical properties of borate glass were found to improve significantly due to the dolomite (CaMg(CO 3 ) 2 ) inclusion. In addition, dolomite can offer a low- phonon environment that is suitable for the enhancement of the ra- diative rate and the quantum efficiency in oxide-based glass hosts. Additionally, the insertion of naturally stable and plentiful dolomite mineral in the BT network can overshoot the main shortcomings asso- ciated with the artificial chemical-based glasses such as hydroscopic nature and high production cost [16–18]. Motivated by this rationale, we prepared Eu 3+ -doped BTD glasses to determine their excellence for https://doi.org/10.1016/j.jnoncrysol.2020.119949 Received 13 September 2019; Received in revised form 20 January 2020; Accepted 28 January 2020 ⁎ Corresponding author. E-mail address: sibkrishna@utm.my (S.K. Ghoshal). Journal of Non-Crystalline Solids 534 (2020) 119949 0022-3093/ © 2020 Elsevier B.V. All rights reserved. T