In the present study, the multiphoton near-infrared downconversion quantum cutting luminescence phenomena of Tm3+ ion in (Y(1-x)Tm(x))(3)Al(5)O(12) powder phosphor, which is currently a hot research topic throughout the world, is reported. The x-ray diffraction spectra, the visible to near-infrared excitation and emission spectra, and fluorescence lifetimes are measured. It is found that Tm:YAG powder phosphor has intense two-photon quantum cutting luminescence, and, for the first time, it is found that Tm:YAG powder phosphor has strong four-photon near-infrared quantum cutting luminescence of 1788 nm (3)F4 → (3)H6 fluorescence of Tm(3+) ion. It is also found that the theoretical up-limit of four-photon near-infrared quantum cutting efficiency is about 282.12%, which results from both the {(1)D2 → (3)F2, (3)H6 → (3)H4} and {(3)H4 → (3)F4, (3)H6 → (3)F4} cross-energy transfers.

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Concentration effect of the near-infrared quantum cutting of 1788-nm luminescence of Tm 3+ ion in (Y 1−𝑥 Tm 𝑥 ) 3 Al 5 O 12 powder phosphor * Chen Xiao-Bo(陈晓波) a) † , Li Song(李 崧) a) , Ding Xian-Lin(丁贤林) b) , Yang Xiao-Dong(杨小冬) a) , Liu Quan-Lin(刘泉林) b) , Gao Yan(高 燕) c) , Sun Ping(孙 萍) a) , and Yang Guo-Jian(杨国建) a) a)