Dependence of the Raman vibration modes on structural properties of Tm:(ScxY1−x)2O3 laser ceramics with 0 ≤ x < 1

We report on micro-Raman spectra of several mixed laser ceramics, i.e., 5at.%Tm: (ScxY1−xO2)3 with x = 0.121, 0.252, 0.489 and 5at.%Tm:Y2O3 ceramic. The samples were fabricated by solid-state pressureless consolidation of nanopowders produced by laser ablation of solid target in air flow. In particular, we studied the influence of Sc3+ content on the active vibration modes in terms of peak positions and shifts, linewidths and shapes: these parameters are relevant for the emission bandwidth of the laser medium. A shift towards higher frequencies is measured with the increase of the Sc3+ content in all samples in particular in (Tm0.048Y0.463Sc0.489O2)3 where the main Raman peaks are placed at 395, 494, 635 cm−1 while their shifts with Tm:Y2O3 are 22.6, 25.1, 40.1 cm−1, respectively. The assignment of the vibrational spectrum was obtained by density functional theory (DFT) with the Perdew-Burke-Enzerhof (PBE) exchange-correlation functional within the harmonic approximation framework.