Publicação: IR-visible upconversion and thermal effects in Pr3+/Yb3+-codoped Ga2O3 : La2S3 chalcogenide glasses
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Iop Publishing Ltd
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IR-visible upconversion fluorescence spectroscopy and thermal effects in pr(3+)/Yb3+-codoped Ga2O3:La2S3 chalcogenide glasses excited at 1.064 mum is reported. Intense visible upconversion emission in the wavelength region of 480-680 nm peaked around 500, 550, 620 and 660 nm is observed. Upconversion excitation of the Pr3+ excited-state visible emitting levels is achieved by st combination of phonon-assisted absorption, energy-transfer and phonon-assisted excited-state absorption processes. A threefold upconversion emission enhancement induced by thermal effects when the codoped sample was heated in the temperature range of 20-200 degreesC is demonstrated. The thermal-induced enhancement is attributed to a multiphonon-assisted anti-Stokes process which takes place in the excitation of the ytterbium and excited-state absorption of the praseodymium. The thermal effect is modelled by conventional rate equations considering temperature-dependent effective absorption cross-sections for the F-2(7/2)-F-2(5/2) ytterbium transition and (1)G(4)-P-3(0) praseadymium excited-state absorption, and it is shown to agree very well with experimental results. Frequency upconversion in singly Pr3+-doped samples pumped at 836 nm and 1.064 mum in a two-beam configuration is also examined.
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Fluorescence, Gallium compounds, Infrared spectroscopy, Lanthanum compounds, Mathematical models, Phonons, Positive ions, Praseodymium, Thermal effects, Ytterbium, Chalcogenide glasses, Conventional rate equations, Infrared visible upconversion fluorescence spectroscopy, Intense visible upconversion emission, Multiphonon assisted anti Stokes process, Thermal induced enhancement, Glass
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Inglês
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Journal of Physics-condensed Matter. Bristol: Iop Publishing Ltd, v. 12, n. 48, p. 10003-10010, 2000.
