Visible luminescence characteristics of Sm 3 þ doped Zinc Alumino Bismuth Borate glasses K. Swapna a , Sk. Mahamuda a , A. Srinivasa Rao a,b,n , T. Sasikala c , L. Rama Moorthy c a Department of Physics, K L University, Green Fields, Vaddeswaram 522502, AP, India b Department of Applied Physics, Delhi Technological University, Delhi 110042, India c Department of Physics, S V University, Tirupathi 517502, AP, India article info Article history: Received 5 June 2013 Received in revised form 11 August 2013 Accepted 17 September 2013 Available online 9 October 2013 Keywords: Samarium Glasses Optical properties JO parameters abstract Zinc Alumino Bismuth Borate (ZnAlBiB) glasses at different compositions doped with 1 mol% of Sm 3 þ ions were prepared by using the melt quenching technique and investigated by XRD, optical absorption, emission and decay curve analysis to understand the visible luminescence of these glasses. From the absorption spectra the JO parameters are evaluated and are used to calculate the radiative properties such as transition probability, radiative lifetime, branching ratio and absorption cross-sections for various fluorescent levels of Sm 3 þ ions. The emission spectra of Sm 3 þ ions doped ZnAlBiB glasses show two intense emission bands 4 G 5/2 - 6 H 7/2 (orange) and 4 G 5/2 - 6 H 9/2 (red) for which the stimulated emission cross-section and branching ratios are evaluated to understand the potentiality of these materials as visible lasers. The decay profiles for the 4 G 5/2 fluorescent level of Sm 3 þ doped ZnAlBiB glasses have been recorded to measure the quantum efficiency (η) of these glasses. The strong visible emissions, large stimulated emission cross-sections, high branching ratios and good quantum efficiencies observed for the present ZnAlBiB glasses suggest the suitability of these glasses as laser and photonic devices operating in visible region. & 2013 Elsevier B.V. All rights reserved. 1. Introduction Optical properties of rare-earth (RE) doped glasses are exten- sively studied for their potential applications in the fields of lasers, fluorescent display devices, optical detectors, wave guides and fibre amplifiers [1–4]. The versatility of glasses, the broader emission and absorption spectra they provide when compared with crystalline hosts, have increasing interest from the perspec- tive of spectroscopic [5] as well as technological point of view [6,7]. The excitation and emissions spectra of RE ions in glasses are due to 4f electronic transitions, which are sensitive to the symmetry, structure of the local environment and on phonon energies of the host glass. The design and development of an optical devise for the above applications require a thorough investigation of optical absorption and luminescence of RE doped glasses. Such studies give the information pertaining to lifetime and quantum efficiency of rare-earth ions. In order to optimise the efficiency of rare-earth doped glasses, the local environment around RE ions has to be changed by changing the glass composi- tion or by changing the concentration of RE ions in a host glass. The ligand fields produced by a host matrix will have considerable influence on the absorption, emission and quantum efficiency of the doped ions. In general a host glass with low phonon energies decreases non-radiative relaxation rates and gives high quantum efficiencies useful for obtaining efficient lasers and optical fibre amplifiers [8]. It is well known that boric acid (B 2 O 3 ) is one of the good glass formers and can form glass alone with good transparency, high chemical durability, thermal stability and good rare-earth ion solubility [9]. However a glass with B 2 O 3 alone will possess high phonon energies (  1300 cm 1 ) which cannot suppress the non- radiative decay process and hence rare-earth ion emissions are strongly reduced. Addition of heavy metal oxides to B 2 O 3 can reduce phonon energies considerably and can give intense fluor- escence suitable for lasers and fibre amplifiers [8]. Heavy metal oxide Bi 2 O 3 besides being a higher valence oxide and having low field strength and high polarisability cannot form glass alone; however in presence of a good glass former like B 2 O 3 , it gives a glass with less phonon energies [10,11]. Moreover, bismuth con- taining glasses can exhibit broad band luminescence in the near- infrared (NIR) region, which finds applications in the fields of telecommunications, tuneable fibre lasers and spectral converters [12]. In recent years glasses containing ZnO have attracted the scientific community because of its role in increasing chemical stability and reducing the thermal expansion of the glass. Their Contents lists available at ScienceDirect journal homepage: www.elsevier.com/locate/jlumin Journal of Luminescence 0022-2313/$ - see front matter & 2013 Elsevier B.V. All rights reserved. http://dx.doi.org/10.1016/j.jlumin.2013.09.035 n Corresponding author at: Department of Applied Physics, Delhi Technological University, Bawana Road, New Delhi 110042, India. E-mail address: drsrallam@yahoo.co.in (A.S. Rao). Journal of Luminescence 146 (2014) 288–294