Green and red luminescence of YSGG:Er under up-conversion and regular excitation at different Er concentrations

Upconversion luminescence in erbium doped transparent oxyfluoride glass ceramics containing hexagonal NaYF4 nanocrystals

“…This is an indication that the 4 S 3/2 and 4 F 9/2 levels excited at 980 nm are populated in two photon processes. Mechanisms of the dominant UCL bands (green and red) in Er 3+ doped materials have been extensively studied elsewhere [46][47][48][49]. In case of the green luminescence, two possible routes, namely, excited state absorption (ESA) and energy transfer upconversion (ETU) can be distinguished.…”

Afterglow phenomenon in Erbium and Titanium codoped GD2O2S phosphors

“…As shown in the figures, it is found that the excitation spectrum monitored by 555 nm is mostly composed by the band absorption near 254 nm and two excitation peaks at 375 nm. The former can be attributed to the host absorption [10], and the later belong to the characteristic absorption of Er 3+ [11]. When the excitation spectrum monitored at 675 nm is checked, not only the strong band absorption at 254 nm can be There are some stronger emission peaks at 540, 555 and 675 nm, which are due to the Er 3+ transition of 4 H 11/2 -4 I 15/2 , 4 S 3/2 -4 I 15/2 and 4 F 9/2 -4 I 15/2 [12].…”

“…Er 3+ in 4 F 9/2 energy level may have two transition approaches: (i) it directly releases nonradiatively to the 4 I 15/2 with red emission; (ii) since the 4 F 9/2 has a very short lifetime which is about 1 ms and 4 I 11/2 has a much longer lifetime of 1.3 ms [15], some Er 3+ will rapidly release to 4 I 11/2 . This permits the energy transfer up-conversion of 4 I 11/2 -4 F 7/2 [11]. Then Er ion will decay nonradiatively to 2 H 11/2 and 4 I 3/2 , thus resulting in 4 S 3/2 -4 I 15/2 and blue luminescence.…”

Optical spectroscopy of Er:YSGG laser crystal

“…Among several Er 3 + -doped garnet crystals, such as Y 3 Sc 2 Ga 3 O 12 (YSGG), Y 3 Al 5 O 12 (YAG) and Ga 3 Gd 5 O 12 (GGG) crystals, Er:YSGG shows lower pumping threshold and higher conversion efficiency [1]. In addition, the up-conversion properties of Er:YSGG crystal have also attracted much attention in recent years [2,3].…”