Excitation scheme for the upper energy levels in a Tm:Yb:BaY2F8 laser crystal

Energy-transfer processes (including upconversion) are quantitatively studied in a Tm:Yb:BaY2F8 laser crystal. Several energy-transfer, cross-relaxation, and upconversion parameters are determined. We prove that at excitation of the crystal via Yb ions, the Tm levels 3F4, 3H4, 3F3,2, 1G4, and 3P0 are populated via Yb-Tm interaction, and the level 1D2 is likely populated owing to 3F3 Tm-3F3 Tm upconversion. The possibility of resonant excited-state absorption at 706 nm and resonant energy-transfer upconversion populating the level 1D2 are discussed. The possibility of avalanche pumping of Tm:Yb:BaY2F8 at 706 nm is shown. © 1997 Optical Society of America