| Автор | P V dos Santos |
| Автор | E A Gouveia |
| Автор | M T de Araujo |
| Автор | A S Gouveia-Neto |
| Автор | S J L Ribeiro |
| Автор | S H S Benedicto |
| Дата выпуска | 2000-12-04 |
| dc.description | IR-visible upconversion fluorescence spectroscopy and thermal effects in Pr<sup>3+</sup>/Yb<sup>3+</sup>-codoped Ga<sub>2</sub>O<sub>3</sub>:La<sub>2</sub>S<sub>3</sub> chalcogenide glasses excited at 1.064 µm 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 Pr<sup>3+</sup> excited-state visible emitting levels is achieved by a 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 °C 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 <sup>2</sup>F<sub>7/2</sub>-<sup>2</sup>F<sub>5/2</sub> ytterbium transition and <sup>1</sup>G<sub>4</sub>-<sup>3</sup>P<sub>0</sub> praseodymium excited-state absorption, and it is shown to agree very well with experimental results. Frequency upconversion in singly Pr<sup>3+</sup>-doped samples pumped at 836 nm and 1.064 µm in a two-beam configuration is also examined. |
| Формат | application.pdf |
| Издатель | Institute of Physics Publishing |
| Название | IR-visible upconversion and thermal effects in Pr<sup>3+</sup>/Yb<sup>3+</sup>-codoped Ga<sub>2</sub>O<sub>3</sub>:La<sub>2</sub>S<sub>3</sub> chalcogenide glasses |
| Тип | paper |
| DOI | 10.1088/0953-8984/12/48/316 |
| Electronic ISSN | 1361-648X |
| Print ISSN | 0953-8984 |
| Журнал | Journal of Physics: Condensed Matter |
| Том | 12 |
| Первая страница | 10003 |
| Последняя страница | 10010 |
| Выпуск | 48 |
