Pr3+-doped B2O3-Bi2O3-ZnO-NaF glasses comprising alkali/mixed alkali oxides for potential warm white light generation, blue laser, and E-+ S-+ C-optical bands amplification applications

Abstract

For six 1 mol% Pr3+-doped B2O3-Bi2O3-ZnO-NaF glasses consisting of single and mixed alkali oxides, optical absorption and visible and near-infrared (NIR) luminescence traits including visible fluorescence decay times were investigated. Judd-Ofelt (J-O) analysis from absorption spectra was performed to calculate J-O parameters Omega(lambda)(lambda = 2, 4, 6) by including and omitting H-3(4) -> P-3(2) transition. Utilizing Omega(2), Omega(4), and Omega(6) values and refractive indices, radiative transition probabilities (A(R)), branching ratios (beta(R)), and radiative lifetimes for all Pr3+ ion's luminescent levels were estimated. For observed intense blue fluorescence band upon 443 nm optical pumping, various parameters considered in designing visible laser systems were evaluated. Pr3+ : Na + K ions comprising glass possesses large spectroscopic quality factor, high A(R) and beta(R), large stimulated emission cross-section (sigma(em)), high quantum efficiency, large gain bandwidth, and significant optical gain for P-3(0) -> H-3(4) transition for a potential blue lasing action among all samples. Further, Commission Internationale de l'eclairage (CIE) coordinates, correlated color temperature (CCT), color rendering index, and luminous efficiency of radiation were derived from visible luminescence spectra and deduced CIE and CCT values represent the neutral or warm white light region. Upon H-3(4) -> P-3(2) excitation, NIR luminescence spectra show P-3(1) + I-1(6) -> (1)G(4), D-1(2) -> F-3(4), and D-1(2) -> (1)G(4) transitions in which broadband (D-1(2) -> (1)G(4)) at 1.3-1.65 mu m range with effective bandwidth similar to 157 nm was obtained for Pr3+ : Na + K ions constituting glass with high A(R) (1938 s(-1)), moderate beta(R) (26%), and large sigma(em) (2.64 x 10(-20) cm(2)) at 1.472 mu m, and its gain profile covers the E-+S-+C-optical communication bands' range for effective broadband amplification operation. (C) 2021 The Author(s). Published by Elsevier B.V.