Enhanced broadband 3 μm emission in Yb3+/Dy3+:YAlO3 crystal under 979 nm excitation

Abstract

Yb3+ ion was introduced as a sensitizer for commercial 980 nm pump source utilization in Yb3+/Dy3+ co-doped YAP crystal for the first time. An intense broadband 3 μm emission (Dy3+:6H13/2 → 6H15/2 transition) in Yb3+/Dy3+:YAP crystal was demonstrated. As compared with Dy3+ singly-doped YAP crystal under 802 nm OPO excitation, the larger emission cross-section (=4.25 × 10−21 cm2) and effective emission bandwidth (=316 nm) were obtained in Yb3+/Dy3+:YAP crystal under 979 nm OPO laser excitation, which make it favorable for tunable lasers. The energy transfer efficiency from Yb3+ to Dy3+ was obtained as high as 97.2%. The greatly reduced near-infrared emission of Yb3+:2F5/2 → 2F7/2 transition and largely shortened lifetime of Yb3+:2F5/2, also reveal the efficient energy transfer from Yb3+ to Dy3+. The energy transfer micro-parameters were calculated by spectral overlapping integral method, and the main energy transfer channel is determined. In addition, the energy dispersive X-ray spectroscopy, X-ray diffraction and Raman spectrum were measured in Yb3+/Dy3+:YAP crystal. Rietveld refinement was also employed to investigate the variation in lattice parameters in Yb3+/Dy3+:YAP crystal. It can be concluded that Yb3+/Dy3+:YAP is an excellent candidate for achieving mid-infrared laser.