Yb-doped mixed-sesquioxide films grown by pulsed laser deposition

•Yb-doped lutetium scandium oxide films are grown via pulsed laser deposition.•Films are compositionally tuned to a 0.1% lattice mismatch with sapphire substrate.•Growth optimization increases the film crystallinity and reduces scattering points.•Films shown to be of single crystal quality. Growth and characterization of compositionally tuned, ytterbium-doped mixed lutetium-scandium oxide, and pure lutetia and scandia crystalline films are presented. Pulsed laser deposition was employed to grow these sesquioxide films, of thicknesses up to 20 µm, on (0 0 0 1)-sapphire substrates. By varying the atomic ratio of lutetium to scandium in the target, the lattice parameter of the resulting films could be tuned to match that of the single-crystal c-cut sapphire substrate and thereby achieve a lattice mismatch of