Visible-to-near-IR luminescence at stepwise up-conversion in Yb,Ho:GGG under IR diode pumping

Photoconductivity and photoluminescence in chemically deposited films of CdSSe:CdCl2,Ho

“…The variations of peak positions with the different concentration of acceptor states appear as a natural consequence of inter−impurity transitions between donor and acceptor levels. [32]. Similarly, the emission at 495 nm corresponds to the transition 5 F 3 ® 5 I 8 in Ho [27].…”

Investigation of up-conversion luminescence properties of RE/Yb co-doped Y2O3 transparent ceramic (RE=Er, Ho, Pr, and Tm)

“…It has a quadratic behavior (slope $ 2) for green and red emissions, which indicates that two pump photons were involved in the up-conversion process. The up-conversion mechanism was expounded in detail [19,20], as shown in Fig. 8: owing to close match of 2 F 5/2 (Yb 3 þ ) and 5 I 6 (Ho 3 þ ), the absorbed energy is easily transferred from the excited Yb 3 þ ion to the 5 I 6 state of Ho 3 þ .…”

Cooperative and charge transfer luminescence in Yb3+-doped yttrium aluminum perovskite (YAlO3)

“…The luminescence in the range of 530-570 nm may be considered as the upconversion energy transfer from the 2 F 7/2 -2 F 5/2 Yb 3+ absorption transition to the Er 3+ 4 I 11/2 -4 F 7/2 absorption transition followed by the 4 S 3/2 -4 I 15/2 emission transition of Er 3+ ions [17][18][19][20]. The luminescence in this region could also originate from 5 I 6 -5 S 2 absorption transition followed by the 5 S 2 -5 I 8 emission transition of Ho 3+ ions or to the Ho 3+ ions absorption transition followed by the 5 S 2 -5 I 8 emission transition [21,22]. The transition 5 F 5 -5 I 8 of Ho 3+ ions, 4 F 9/2 -4 I 15/2 of Er 3+ ions or 1 G 4 -3 H 4 of Tm ions may be responsible for the upconversion luminescence in the range of 630-680 nm [23,24].…”