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

Abstract

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 2F7/2 (ground state) and 2F5/2 (excited state) Stark levels of the most populated C2 symmetry site, and on the presence of the magnetic dipole transitions from the C3i (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 2F5/2(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.

Microstructure and properties characterization of Yb:Lu2O3 transparent ceramics from co‐precipitated nano‐powders

“…[1][2][3] It has been demonstrated that Lu 2 O 3 can be doped with various rare-earth (RE) ions for laser emission at different wavelengths, such as Yb 3+ and Nd 3+ at 1 μm, Tm 3+ and Ho 3+ at 2 μm as well as Er 3+ at 3 or 1.5 μm. [4][5][6][7][8][9][10][11][12] Among these trivalent RE ions, doping with Yb 3+ has the least impact on the crystallographic and physical properties of the host due to the comparable mass and ionic radius of metal ions, which results in weak lattice distortions, low scattering losses, excellent thermal properties, and ease to obtain different doping levels. 9,13 It is known that high thermal conductivity at high doping concentrations is advantageous to laser power scaling due to efficient heat dissipation from the gain media.…”

“…Cubic sesquioxide Lutetia (Lu 2 O 3 ) material has attracted considerable interest as a laser host due to its potential applications in high‐power solid‐state lasers (SSL) 1–3 . It has been demonstrated that Lu 2 O 3 can be doped with various rare‐earth (RE) ions for laser emission at different wavelengths, such as Yb 3+ and Nd 3+ at 1 μm, Tm 3+ and Ho 3+ at 2 μm as well as Er 3+ at 3 or 1.5 μm 4–12 . Among these trivalent RE ions, doping with Yb 3+ has the least impact on the crystallographic and physical properties of the host due to the comparable mass and ionic radius of metal ions, which results in weak lattice distortions, low scattering losses, excellent thermal properties, and ease to obtain different doping levels 9,13 .…”