Nonlinear spectroscopic properties of Yb3+-doped sesquioxides Lu2O3 and Sc2O3.

We report on the measurements of near-UV excited-state absorption (ESA) spectra and refractive index changes (RICs) in the two ytterbium doped laser crystals Yb:Lu2O3 and Yb:Sc2O3. ESA is assigned to ligand-to-metal charge transfer (LMCT) absorption transitions and RICs to the polarizability changes experienced by the Yb3+ ions due to these strong electric-dipole allowed absorption bands.