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Influence of Synthesis Conditions for Yb:CaWO4 Single Crystals on the Down-Conversion Luminescence of Yb3+ Ions in These Crystalsстатья
Статья опубликована в журнале из списка RSCI Web of Science
Информация о цитировании статьи получена из
Web of Science
Статья опубликована в журнале из списка Web of Science и/или Scopus
Дата последнего поиска статьи во внешних источниках: 14 октября 2021 г.
- Авторы: Subbotin K.A., Titov A.I., Lis D.A., Chernova E.V., Lis O.N., Smirnov V.A., Zharikov E.V., Shcherbakov I.A.
- Журнал: Physics of Wave Phenomena
- Том: 29
- Номер: 3
- Год издания: 2021
- Издательство: Allerton Press Inc.
- Местоположение издательства: United States
- Первая страница: 187
- Последняя страница: 198
- DOI: 10.3103/s1541308x21030122
- Аннотация: Yb:CaWO 4 and Yb, Nb:CaWO 4 single crystals have been grown by the Czochralski method in air and in protective atmospheres and subjected to additional annealing in air, in CO/CO 2 atmosphere, and in forevacuum. The optical absorption spectra in the range from 250 to 1500 nm and the luminescence spectra of these crystals in the visible and near-IR spectral regions upon UV excitation have been investigated. It is shown that additional introduction of Nb 5+ ions into Yb:CaWO 4 crystal increases by an order of magnitude (almost to unity) the Yb 3+ distribution coefficient between CaWO 4 crystal and melt. It is found that optical excitation of the crystals in the range of 260–355 nm induces down-conversion luminescence of Yb 3+ ions from the 2 F 5/2 level in the vicinity of 1 μm. An increase in the oxidative potential of synthesis atmosphere, as well as the introduction of niobium into the crystal composition, weakens this luminescence. A consistent pattern explaining the nature of the donor centers involved in down-conversion population of excited state 2 F 5/2 of Yb 3+ in the crystals is proposed. Within this pattern, Yb 2+ ions play the role of these donor centers. Another (much less efficient) mechanism of population of the 2 F 5/2 level is intracenter relaxation from the higher-lying charge transfer excited state within Yb 3+ ions. At the same time, it is confirmed that color centers based on oxygen vacancies and partially reduced tungsten ions, as well as self-trapped excitons on tungstate complexes, are not involved in population of the excited state 2 F 5/2 of Yb 3+ ions, and the optical centers formed in Yb:CaWO 4 crystals as a result of vacuum annealing suppress ytterbium luminescence.
- Добавил в систему: Субботин Кирилл Анатольевич