Epitaxial Growth of Lattice Matched KY1-x-yGdxLuy(WO4)2 Thin Films on KY(WO4)2 Substrates for Waveguiding Applications

The main purpose of this work was the determination of the composition of a KY1-x-yGdxLuy(WO4)(2) layer grown by liquid phase epitaxy (LPE) technique on KY(WO4)(2) substrate having enough refractive index contrast and appropriate lattice mismatch (f(hkl)) to act as planar waveguides. To achieve this we have grown KY1-x-yGdxLuy(WO4)(2) single crystals by the flux method and characterized them in terms of chemical composition, structure and refractive indices. A high quality epitaxial layer of KY0.58Gd0.Lu-22(0.20)(WO4)(2) with a thickness of 10 mu m was grown on a b orienter KY(WO4)(2) Substrate by LPE. At lambda = 632.8 nm this g planar waveguide can support five and four guided modes along the N-g and N-m directions, respectively and five TM modes along N-p direction.