Growth, spectroscopy, and laser characterization of Er:KGdYbY(WO) epitaxial layers.

We report on the composition of Er-doped KGdYbY(WO) layers to be grown onto undoped KY(WO) substrate providing fine lattice matching and high refractive index contrast with the substrate and fabrication of high optical quality Er(1.3  at. %):KGdYbY(WO) epitaxial layers with thickness up to 180 μm.