Judd-Ofelt modeling, stimulated-emission cross-sections and non-radiative relaxation in Er3+:K2YF5 crystals

Judd-Ofelt(J-O) analysis of Er3+:K2YF5 crystals has been performed to evaluate the spontaneous emission probabilities, radiative lifetimes and luminescence branching ratios for Er3+ions from the viewpoint of developing novel laser materials. The derived J-O parameters are Ω2=1.216, Ω4=0.647 and Ω6=0.459×10−20 cm2 for a K2Y0.9Er0.1F5 crystal. Radiative lifetimes of the 4I13/2and 4I11/2 states are as long as 14.9 ms and 17.4 ms, respectively. Stimulated-emission cross-sections spectra are presented for the 4S3/2→4I15/2, 4I13/2→4I15/2 and 4I11/2→4I13/2 transitions. The maximum σSE values are 1.5×10−20 cm2 at 558 nm, 0.72×10−20 cm2 at 1531 nm and 0.40×10−20 cm2 at 2705 nm,respectively. Non-radiative relaxation rates have been determined for the excited-states of Er3+ions in K2YF5. It is assumed that Er3+:K2YF5 crystals are promising for green up-conversion lasers.