title: Optical properties and spectroscopic study of different modifier based Pr(3+):LiFB glasses as optical amplifiers.
abstract: In this paper, we report the preparation and optical characterization of Pr(3+) doped lithium fluoro borate (LiFB) glasses for six different chemical compositions of Li2B4O7-BaF2-NaF-MO (where M=Mg, Ca, Cd and Pb), Li2B4O7-BaF2-NaF-MgO-CaO and Li2B4O7-BaF2-NaF-CdO-PbO. The structural and optical properties of these glasses were characterized by X-ray powder diffraction (XRD), scanning electron microscope (SEM), Fourier transform infrared spectroscopy (FTIR), optical absorption and photoluminescence techniques. The optical absorption spectra of Pr(3+) ions in LiFB glasses have been recorded in the UV-VIS-NIR region. The optical absorption data are used to calculate various spectroscopic parameters such as Racah (E(1), E(2), E(3)) and spin-orbit interaction (ξ4f) parameters. Judd-Ofelt (J-O) (Ωλ where λ=2, 4 and 6) intensity parameters were determined by applying J-O theory, which in turn used to calculate the radiative properties such as radiative transition probabilities (A), radiative lifetimes (τR), integrated absorption cross-sections (Σ) and branching ratios (βr) for all emission levels of Pr(3+) ion in different LiFB glass matrices. By using the J-O theory and luminescence parameters, stimulated emission cross sections (σp) of prominent transitions, (3)P0→(3)H4 and (1)D2→(3)H4 of Pr(3+) ion in all LiFB glasses were calculated. (3)P0→(3)H4 possesses higher branching ratios and stimulated emission cross-sections for the Pr(3+):LiFB(Mg-Ca) glass, which can be used as a best laser excitation. The optical gain parameter (σpxτR) was noticed higher in Pr(3+):LiFB(Mg-Ca) and Pr(3+):LiFB(Cd-Pb) glasses for the transition (3)P0→(3)H4 transition, and these glasses have potential for optical amplification at 488 nm wavelength.
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India; Department of Physics, University of the Free State, Bloemfontein ZA9300, South Africa. Electronic address: balakrishna.veera@gmail.com.
authors.forename: A
authors.initials: A
authors.lastname: Balakrishna
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India.
authors.forename: S
authors.initials: S
authors.lastname: Babu
authors.affiliation: Department of Physics, University of the Free State, Bloemfontein ZA9300, South Africa.
authors.forename: Vinod
authors.initials: V
authors.lastname: Kumar
authors.affiliation: Department of Physics, University of the Free State, Bloemfontein ZA9300, South Africa. Electronic address: ntwaeab@gmail.com.
authors.forename: O M
authors.initials: OM
authors.lastname: Ntwaeaborwa
authors.affiliation: Department of Physics, Sri Venkateswara University, Tirupati 517 502, India. Electronic address: ratnakaramsvu@gmail.com.
authors.forename: Y C
authors.initials: YC
authors.lastname: Ratnakaram
keywords: Branching ratios; Judd-Ofelt theory; Luminescence; Stimulated emission cross-sections