title: Development of ytterbium-doped oxyfluoride glasses for laser cooling applications.
abstract: Oxyfluoride glasses doped with 2, 5, 8, 12, 16 and 20 mol% of ytterbium (Yb(3+)) ions have been prepared by the conventional melt-quenching technique. Their optical, thermal and thermo-mechanical properties were characterized. Luminescence intensity at 1020 nm under laser excitation at 920 nm decreases with increasing Yb(3+) concentration, suggesting a decrease in the photoluminescence quantum yield (PLQY). The PLQY of the samples was measured with an integrating sphere using an absolute method. The highest PLQY was found to be 0.99(11) for the 2 mol% Yb(3+): glass and decreases with increasing Yb(3+) concentration. The mean fluorescence wavelength and background absorption of the samples were also evaluated. Upconversion luminescence under 975 nm laser excitation was observed and attributed to the presence of Tm(3+) and Er(3+) ions which exist as impurity traces with YbF3 starting powder. Decay curves for the Yb(3+): (2)F5/2 → (2)F7/2 transition exhibit single exponential behavior for all the samples, although lifetime decrease was observed for the excited level of Yb(3+) with increasing Yb(3+) concentration. Also observed are an increase in the PLQY and a slight decrease in lifetime with increasing the pump power. Finally, the potential of these oxyfluoride glasses with high PLQY and low background absorption for laser cooling applications is discussed.
authors.affiliation: Department of Engineering Physics, Polytechnique Montréal, 6079, Station Centre-ville, Montréal H3C 3A7, Canada.|Centre d'Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, Québec G1V 0A6, Canada.
authors.forename: Kummara Venkata
authors.initials: KV
authors.lastname: Krishnaiah
authors.affiliation: Department of Engineering Physics, Polytechnique Montréal, 6079, Station Centre-ville, Montréal H3C 3A7, Canada.
authors.forename: Elton Soares
authors.initials: ES
authors.lastname: de Lima Filho
authors.affiliation: Centre d'Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, Québec G1V 0A6, Canada.
authors.forename: Yannick
authors.initials: Y
authors.lastname: Ledemi
authors.affiliation: Department of Engineering Physics, Polytechnique Montréal, 6079, Station Centre-ville, Montréal H3C 3A7, Canada.
authors.forename: Galina
authors.initials: G
authors.lastname: Nemova
authors.affiliation: Centre d'Optique, Photonique et Laser, 2375 Rue de la Terrasse, Université Laval, Québec G1V 0A6, Canada.
authors.forename: Younes
authors.initials: Y
authors.lastname: Messaddeq
authors.affiliation: Department of Engineering Physics, Polytechnique Montréal, 6079, Station Centre-ville, Montréal H3C 3A7, Canada.|Department of Electrical Engineering, Polytechnique Montréal, 6079, Station Centre-ville, Montréal H3C 3A7, Canada.
authors.forename: Raman
authors.initials: R
authors.lastname: Kashyap