Synthesis and characterisation of tantalum-incorporating silica hybrid sol-gel thin films for optical applications

A new acrylate-modified silica incorporating tantalum is synthesised via a sol-gel route. After deposition, the few micron-thick films can be photo-polymerised by UV-irradiation. FTIR spectroscopy gives a first insight into the curing process and the chemical structure of the hybrid material. The refractive index of the layers can be modulated by varying the concentration of tantalum in the material. Coatings exhibit a good transparency in the blue range of the optical spectrum. Finally, the propagation losses are low enough to make the material suitable for applications in integrated optics.