Avalanche up-conversion processes in Pr, Yb-doped materials

Upconversion and Anti-Stokes Processes with f and d Ions in Solids

“…In the case of the codoped Yb-Pr system, real avalanche has been reached. 266 In this system, see Figure 38, the first nonresonant excitation step is in the Yb 3+ ion, which transfers to the metastable state 1 G 4 (Pr 3+ ) from which the resonant second step up to 3 P 0 (Pr 3+ ) takes place. The cross-relaxation step within two Pr 3+ ions feeds the metastable state 1 G 4 (Pr 3+ ) and the back transfer to Yb 3+ again feeds the 1 G 4 (Pr 3+ ) metastable state.…”

“…274 The energy scheme and avalanche processes, which are involved, are the ones described in the previous subsection for the avalanche process with Yb-Pr codoping. 266 Laser emission is from the 3 P 0 -3 F 2 transition of Pr 3+ at 0.635 µm with a record output of 1020 mW. The pumping is from two Tisapphire lasers providing 5.51 W at 0.850 µm.…”

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

“…10. Unlike the other RE ions, under 980 nm pumping, the green emission from Pr 3 þ ion is mainly attributed to the photon avalanche mechanism [22,23]. The process can be expressed as follows [24]:…”

Host sensitized near infrared to visible photon upconversion in 1% Re4+ doped Cs2NaYbBr6

“…All the f-f oscillator strength is thus concentrated in the 2 F 7/2 ↔ 2 F 5/2 transition. Since there are no further absorptions up to the UV, Yb 3+ is widely used as an upconversion (UC) sensitizer in mixed Ln/Ln containing materials with Tm 3+ [1], Er 3+ [2], Dy 3+ , Ho 3+ [3], Nd 3+ , Pr 3+ [4] as the active UC ions. Both upconversion phosphor and laser materials are based on this principle.…”