Upconversion-induced ultraviolet emission in Ho3+ doped SrLaGa3O7 and SrLaGaO4 crystals

Optical spectroscopy of heavily Ho3+-doped BaY2F8 crystals

“…These emission features could be assigned as originating from the 5 G 4 level, but the observation that the decay time is in practice identical to the one of ( 5 F 4 , 5 S 2 ) may also suggest an alternative explanation. In fact BaY 2 F 8 :Ho 3+ crystals are characterized by efficient upconversion processes [23,25] and UV upconversion of Ho 3+ has been very well documented [26][27][28]. It is therefore conceivable that the intense laser excitation gives rise to upconverted emission from highly excited states, with the thermalized metastable ( 5 F 4 , 5 S 2 ) levels as intermediate states.…”

Ultraviolet and violet upconversion luminescence in Ho3+-doped Y2O3 ceramic induced by 532-nm CW laser

“…Most upconversion studies on Ho 3+ -doped materials were mainly focused on infrared and visible regions. There are also a few papers devoted to the studies of UV and violet upconversion fluorescence under IR or red laser excitation [5,7,10,11]. Here we report the generation of blue, violet, and ultraviolet upconversion luminescence spectra in the range of 290-450 nm by the excitation of a compact continues-wave 532 nm green solid-state laser in Y 2 O 3 :Ho 3+ ceramic.…”

Luminescence properties of a new blue-emitting phosphor Ce3+-doped CaLaGa3S7

“…Rare-earth-doped melilite compounds of general formula ABC 3 O 7 where A = Ca, Sr, Ba; B = La, Gd; and C = Al, Ga have been extensively investigated over the last few decades [1][2][3][4]. Examples of these are Cr 4+ -doped SrXGa 3 O 7 (X = La, Gd) [5], Dy 3+ , Pr 3+ and Nd 3+ doped SrLaGa 3 O 7 single crystals [6], Ho 3+ -doped SrLaGa 3 O 7 [7], Ce 3+ , Pr 3+ and Tb 3+ doped SrLaGa 3 O 7 [8].…”