Spectroscopic characteristics of Tm3+ in Tm and Tm, Nd, Yb:Sc2O3 ceramic

The spectroscopic investigation of Tm3+ or (Nd, Yb, Tm)-doped Sc2O3 transparent ceramics, as laser-active media for visible and IR emission, was performed. The spectra are dominated by Tm3+ ions in sites of C2 symmetry and an energy level scheme and other spectral parameters were determined. The strong concentration quenching of 3H4 level emission in Tm:Sc2O3 at 300 K is discussed by considering the resonant cross-relaxation (3H4→3F4)-(3H6→3F4) process and multipolar interactions of various orders. The main energy-transfer processes leading to the blue upconversion emission from the 1G4 Tm3+ level in (Tm, Nd, Yb):Sc2O3 ceramic, under pulsed pumping at 808.3 nm were evidenced