Ag:TiO2 nanocomposite films have been synthesized by sol-gel method followed by electron beam physical vapour deposition. Targets for this deposition were prepared by a hydraulic press using a powder containing Ag and TiO2 prepared by sol-gel technique. Microstructure, surface, and plasmonic properties of nanocomposite films were studied using glancing angle X-ray diffractometer, atomic force microscopy, field emission secondary electron microscopy, and UV-Vis spectroscopy. Microstructural study reveals that Ag nanoparticles are embedded in TiO2 matrix consisting of mixed phases of anatase and rutile. Size estimation using Scherrer formula reveals that average crystallite size of Ag nanoparticles is 23？nm. Surface morphological studies indicate that deposited films are uniform and intact to the substrate and have very low value of root mean square roughness. Optical studies exhibit a surface plasmon resonance induced absorption band in visible region, which is the characteristic feature of Ag nanoparticles. The intensity of this absorption band is found to increase with the increase in deposition time. Multiple peaks observed in absorption band were explained using the concepts of extended Mie scattering. Preliminary experiments also suggested that these nanocomposite films exhibit promising photocatalytic properties, which can be used for water treatment. 1. Introduction Plasmonic nanocomposites have been recently found to be the centre of attraction for their potential use in photocatalytic, nanosensing and optoelectronic and biomedical applications [1–6]. For example, Au nanoparticles of 3–8？nm diameters have been shown to tune the catalytic properties [1, 2]. Along with acting as an interface with the nanoscale, plasmonic nanocomposites can also change light-matter interactions at a very fundamental level. The possibility to confine light in subwavelength mode volume cavities has shown many optical processes that benefit from high optical quality factors and ultrasmall electromagnetic mode volumes [3]. This is the reason why plasmonic nanocomposites can be used to enhance a range of nonlinear processes in ultracompact device geometries, modify the temporal and spatial properties of light emitters, control both near and far field thermal radiation pathways, and manipulate light using new optical materials with engineered refractive indices [3]. Kumar et al. have shown plasmonic and nonlinear optical properties in Ag:ZrO2 plasmonic nanocomposites [5]. Akhavan reported interesting antibacterial activities of Ag-TiO2/Ag/a-TiO2 nanocomposite thin film
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