Intense red upconversion emission of Yb/Tm/Ho triply-doped tellurite glasses.
By conventional melting and quenching methods, 3Yb2O3-0.2Tm2O3-xHo2O3 (wt%, x=0.2~1.2) was doped into an easily fiberized tellurite glass with composition of 78TeO2-10ZnO-12Na2O (mol%) to form YTH-TZN78 glasses. Under 976 nm excitation, the direct sensitizing effect of Yb ions (Yb→Ho) and indirect sensitizing and self-depopulating effects of Tm ions (Yb→Tm→Ho) were found to present intense red upconversion emission at 657 nm (Red, Ho:5F5→5I8) and were responsible for the absence of the usually observed 484 nm emission (Blue, Tm:1G4→3H36). Regardless of the dopant concentration of Ho ions, the intensity of the red emission at 657 nm (Red, Ho:5F5→5I8) is about three times stronger than that of the green one at 543 nm (Green, Ho:5S2→5I8). For this certain red emission at 657 nm, 0.4 wt% Ho2O3-doped YTH-TZN78 glass was found to present the highest emission intensity and is therefore determined as a promising active tellurite glass for red fiber laser development.
Yb3+/Tm3+/Ho3+ tri-doped silica-based glass: intense up-conversion and broad near-infrared emission
The Yb3+/Tm3+/Ho3+ tri-doped silica-based glasses are firstly prepared by the CO2 laser sintering method. The up-conversion (UC) luminescence and near-infrared emission properties are investigated under 980 nm excitation. Broad emission band with the full width at half maximum of 400 nm within the infrared spectral region around 2 μm is obtained. In addition, the energy transfer mechanism among Yb3+, Tm3+, and Ho3+ are discussed in detail. The experimental results show that the Yb/Tm/Ho tri-doped silica-based glasses prepared by the CO2 laser sintering method can be the potential materials for white light source and infrared laser operating at 2 μm.
Absorption and emission properties of Ho3+ doped lead–zinc–borate glasses
Abstract This paper reports on the affect of lead content on the absorption and emission spectra of the Ho 3+ ion doped lead–zinc–borate glasses in the composition (mol%) of (20 −  x )PbO–20ZnO–(59 +  x )B 2 O 3 –1.0Ho 2 O 3 where x  = 0, 5,10,15 of PbO content with λ exc  = 405 nm. The experimental absorption band energies have satisfactorily been correlated with the theoretical results with an r.m.s deviation of zero with the following correction factors obtained by a least square fit analysis: Δ E 1  = 348.495936 cm − 1 , Δ E 2  = 1.436043 cm − 1 , Δ E 3  =  46.481575 cm − 1 , Δ ξ 4f  = − 28.512979 cm − 1 , Δ α  = 55.508936 cm − 1 , Δ β  = − 1394.339908 cm − 1 and Δ γ  = 1208.424336 cm − 1 . By applying the Judd–Ofelt intensity parameter Ω 2 has been found to be linearly decreasing with the PbO content from 5 to 10 mol% and then increasing. And also radiative ( A , A T , β , τ r ) characteristic factors of the luminescent transitions ( 5 I 8  ←  5 F 3,4,5 and 5 S 2 ) of the glasses have been evaluated. Stimulated emission cross-sections ( σ p E ) of the measured emission transitions of holmium glasses have also been computed.