LAUSR

A novel transparent 4.76 at.% Tm:(Lu2/3Sc1/3)2O3 “mixed” sequioxide ceramic is synthesized by hot isostatic pressing (HIP) at 1800 °C / 195 MPa in an Ar atmosphere. Its structure is studied by scanning electron microscopy, X-ray diffraction, and Raman spectroscopy. The spectroscopic properties of the Tm3+ ion are described within the Judd-Ofelt theory, which resulted in intensity parameters of Ω2 = 2.429, Ω4 = 1.078 and Ω6 = 0.653 [10−20 cm2]. For the 3F4 → 3H6 transition, the maximum stimulated-emission cross-section σSE is 7.15 × 10−21 cm2 at 1951 nm. The radiative lifetime of the 3F4 state is 4.01 ms. Under diode-pumping at 802 nm, a microchip Tm:(Lu,Sc)2O3 ceramic laser generated ~1 W at 2100 nm with a slope efficiency of 24%. The spectroscopic and laser properties of the Tm:(Lu,Sc)2O3 ceramic are compared with those of a Tm:LuScO3 single crystal. The ceramic exhibits very broad and flat gain cross sections, which is promising for ultrashort pulse generation.