Luminescence and radiative decay of Er³⁺in Cs₂NaErCl₆

Upconversion fluorescence of Er3+ trace impurity ions and Raman study in K2YF5:0.1 mol% Tm3+ single crystal

“…These indicate that the ESA process happens from 4 S 3/2 level. Our observed upconversion emission bands with 514.5 nm laser excitation, as well as the corresponding upconversion mechanism, are quite different from those in the previous works [8,16], in which, under the same laser excitation, 385 nm ( 4 G 11/2 → 4 I 15/2 ) firstly, by absorbing one 514.5 nm laser photon, Er 3+ ions are excited from the ground state to 2 H 11/2 , and then relax quickly to long lifetime level 4 S 3/2 . From there it absorbs the second photon and transits to the 4 G 9/2 level.…”

Blue upconversion of cubic Gd2O3:Er produced by green laser

“…Gan et al [15] and Tanner [16] also reported the upconversion spectra of Er 3+ ions in flurozirconate glasses and Cs 2 NaErCl 6 under 514.5 nm laser excitation, respectively. According to their experiment results, Tanner attributed the upconversion emission from 2 H 9/2 level to a cross relaxation process involving the 4 I 13/2 , 4 S 3/2 initial levels.…”

“…These spectra exhibit four groups of upconversion emission peaks around 388-391, 400-420, 469-479, and 489-505 nm. According to the energy level structure of Er 3+ and previous works [12,[16][17][18], some assignments can be made: 4 Fig. 3, it is clear that the emissions around 400-420 nm can be separated into two parts: 400-407.5 nm region and 407.5-420 nm region.…”

“…Most upconversion studies of Er-doped materials were focused on infrared laser excitation [1][2][3][4][5][6][7][8][9][10][11][12][13][14] because the intermediate levels 4 I 9/2 (around 12491 cm −1 ) and 4 I 11/2 (around 10276 cm −1 ) of Er 3+ ions can be conveniently populated by commercial low-cost high-power near-infrared laser diodes. However, the investigation of violet and blue upconversion under visible laser excitation is very scarce [15][16][17][18]. Fortunately, the 4 S 3/2 level, whose lifetime is longer than that of other states in the visible range, provides an available intermediate state for this kind of study [17].…”

Energy Transfer and Up-Conversion in the Erbium Elpasolites Cs2NaErxY1-xCl6

“…The energy levels of erbium both, as a free ion and in the elpasolite lattice, have been extensively investigated and are well catalogued [1,2]. The odd parity vibrational modes of the ErCl36+ moiety, V6, 1/4 and 1/3, occur at about 80, 120, and 280 cm -1 and are readily observed in the vibronic transitions.…”