文档介绍：第五节Sm2+离子荧光漂白photobleaching?In 1997, Krebsobserved firstly the photobleaching of Sm2+selectively doped epitaxial CaF2film. decreased non-exponentially ; the shape of the emission line was not altered ?In 2001, more materials doped with Sm2+were found to have the bleaching effect by Mikhail and Hulliger. Single crystals of CaF2, SrF2, BaFCl, SrFCl, , SrB4O7and ceramic samples of BaCl2, SrSO4?To explain the bleaching phenomenon, they assumed a nonradiative decay mechanismthat resulted in a decrease of the Sm2+fluorescence. An important thing declared was the reversible bleachingof the Sm2+luminescence; however the reversible bleaching in their work was only available for the broadband transition 4f55d-4f6of Sm2+in the crystal sample of CaF2:Sm2+.?Additionally, all the decrease processes of bleaching were treated exponentiallyby the authors, which maybe was a mistake.?Tanakareported a reversible photochromic processthey observed in BaClF: Sm2+in 2001. They found that the fluorescence intensity of Sm2+in BaClF decreased under the excitation at 325 nm and recovered with the 488-nm light at room temperature. The reversible bleaching was interpreted in terms of that Sm2+ was photoionized to Sm3+by 325-nm light and the excited electrons were captured by halogen vacancies of BaClF, while the trapped electrons were released under the 488-nm light and Sm3+was reduced to Sm2+.?Here, we report some novel results on the photobleaching fluorescence intensity of Sm2+decreased as much as 96% in 30 influenced by the processes used for sample preparation , such as reduction, grinding or x-ray biexponential decrease mode was found, ~ tens of seconds, ~hundreds of under the laser irradiation of blue, green or even red Sm3+ions generated, no relative spectral change and no lifetime threshold: 5D0→ identical mechanism, the bination of the electrons released from Sm2+io