title: Enhanced 2 μm broad-band emission and NIR to visible frequency up-conversion from Ho3+/Yb3+ co-doped Bi2O3-GeO2-ZnO glasses.
abstract: In this work, a new and non-conventional oxide glass composition based on Bi2O3-GeO2-ZnO system has been formulated with an aim to realize low phonon oxide glass and elucidate its performance when co-doped with Ho(3+)/Yb(3+) for the energy transfer based NIR emission at 2 μm from Ho(3+) ions under Yb(3+) excitation. The glass with 1.0 mol% Ho2O3 and 0.5 mol% Yb2O3 has exhibited maximum energy transfer rate (3602 s(-1)) and energy transfer efficiency (65.92%). Important radiative properties have been predicted for emission transitions of Ho(3+) ions using intensity parameters derived from measured absorption spectra using standard Judd-Ofelt theory. At lower acceptor ion concentration (0.1 mol%), an efficient NIR to visible up-conversion emission has been observed based on two photon absorption process which has found to be reduced significantly at higher Ho(3+) concentrations with simultaneous enhancement in 2 μm emission. Hence, this newly developed glass codoped with Yb(3+)/Ho(3+) is promising glass for sensitized 2 μm emission applications as broad band tunable lasers because of the combination of low phonon energy (707 cm(-1)), high energy transfer efficiency, moderately high emission cross-section (5.33×10(-21) cm(2)) and larger effective half-width of the emission band value of 169 nm.
authors.affiliation: Glass Division, Glass Science and Technology Section, CSIR-Central Glass and Ceramic Research Institute, 196, Raja S.C. Mullick Road, Kolkata 700 032, India.
authors.forename: Kaushik
authors.initials: K
authors.lastname: Biswas
authors.forename: Atul D
authors.initials: AD
authors.lastname: Sontakke
authors.forename: R
authors.initials: R
authors.lastname: Sen
authors.forename: K
authors.initials: K
authors.lastname: Annapurna
mesh_terms: D001729:Bismuth / Q000737:chemistry*; D005857:Germanium / Q000737:chemistry*; D005898:Glass / Q000737:chemistry*; D006695:Holmium / Q000737:chemistry*; D049449:Luminescence; D015018:Ytterbium / Q000737:chemistry*; D015034:Zinc Oxide / Q000737:chemistry*
chemical_list: D005857:Germanium; C040516:germanium oxide; C033301:bismuth oxide; D015018:Ytterbium; D015034:Zinc Oxide; D001729:Bismuth; D006695:Holmium