Formation of polycrystalline TiO2 on the ablated surfaces of RbTiOPO4 single crystals by thermal annealing

Abstract

We investigated the structural effects that ultrafast laser ablation has on RbTiOPO₄ (RTP) single crystals. Raman scattering analysis revealed that a polycrystalline layer of RTP substituted the original material on the surface of the microstructured areas which is mainly responsible for the roughness observed in these structures. A later annealing treatment on the ablated samples resulted in the formation of a layer of sub-micrometric particles of TiO₂ in a mixed form of anatase and rutile, due to the decomposition of the polycrystalline RTP layer. This allows the development of engineering strategies to fabricate RTP–TiO₂ composites, with mixed properties, that might allow the combination of the non-linear optical properties of RTP and the light dispersive and electrical properties of TiO₂.