High efficiency continuous wave and Q-switched laser based on an orthorhombic Yb:GdScO₃ crystal in the (112) direction with a broad emission bandwidth of 93 nm

Herein, we demonstrate a broad emission bandwidth of 93 nm with the orthorhombic Yb:GdScO 3 crystal along the (112) direction, which is about 3.7–7.8 times wider than that of cubic sesquioxide crystals. By investigating the distorted RE2O x ligands and their association with lattice vibrations, the inhomogeneous broadening was found to be dependent on local crystal polarization and electron-phonon interaction. Moreover, the (112) direction sample has a small emission cross-section of 0.42 × 10 −20 cm 2 and better thermal symmetry, which allow it to achieve a continuous wave (CW) laser with a slope efficiency of 62%, a passively PdSe 2 Q-switched laser with an average output power of 1.69 W, a slope efficiency of 43%, and a pulse width of 272.9 ns. We believe this to be the first investigation of the effective spectral broadening and Q-switch operations based on the orthorhombic Yb:GdScO 3 crystal in the (112) direction.