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

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.