Intense 3.9 µm emission of Ho3+ doped YAlO3 single crystal

The Ho3+-doped YAlO3 (YAP) crystal was successfully grown using the Czochralski technique. An intense 3.9 µm emission in Ho:YAP crystal was observed for the first time. The spectroscopic parameters were determined by Judd-Ofelt theory based on the measured polarized absorption spectra. The intensity parameters Ω2,4,6, exited state lifetimes, branching ratios, and emission cross-sections were calculated. Under optical pumping at 890 nm, an intense 3.9 µm emission with a bandwidth of 190 nm at full width half maximum was observed. The maximum emission cross section of Ho:YAP crystal is estimated to be 0.302 × 10−20 cm2 at 4096 nm. The decay lifetime of the level was measured to be 0.103 ms. We propose that the Ho:YAP crystal may be a promising material for 3.9 µm laser applications.