Specifics of Spectroscopic Features of Yb³⁺-Doped Lu₂O₃ Laser Transparent Ceramics

Some specifics of spectroscopic and laser properties of Yb³⁺ dopant are shown in Yb³⁺-doped Lu₂O₃ cubic sesquioxide transparent ceramics, a very important laser material, fabricated by Akio Ikesue using the method based on solid-state mixing of oxides and sintering by hot isostatic pressing (HIP) technique. For instance, despite the simplicity of Yb³⁺ electronic configuration, it is emphasized that a lot of precautions need to be considered during the evaluation and the assignment of Yb³⁺ experimental data in this sample and also in all Yb³⁺-doped materials. First, we focus our discussion on the position of ²F_7/2 (ground state) and ²F_5/2 (excited state) Stark levels of the most populated C₂ symmetry site, and on the presence of the magnetic dipole transitions from the C_3i (S₆) inversion symmetry site. Then, we point out the strong influence of the self-trapping and the self-quenching processes on the measurement of the ²F_5/2(5) upper level decay time which needs the pin-hole method. Finally, we comment on the spectrum of the tuneable laser emission behaviour near 1033 nm with respect to the losses of the laser cavity without the laser emission near 1080 nm, as observed in other laser materials.