In this paper, we report a new, low-cost, and facile solvothermal approach to synthesize visible-light-active S-doped TiO 2 (S-TiO 2 ) by using dimethyl sulfoxide (DMSO) as both the S source and the solvent. Energy-dispersive X-ray (EDX) and X-ray photoelectron spectroscopy (XPS) solidly confirmed the presence of S element in the final product. The as-prepared S-TiO 2 nanoparticles exhibited excellent and longterm stable photocatalytic performance for the degradation of organic pollutants under visible and indoor sunlight illumination. The catalyst still maintained high photoactivity even after several months of exposure to the indoor sunlight irradiation. This result suggests a new approach to achieve stable and highly efficient solar light driven photocatalysts for water purification.

A cw, visible laser beam self-traps by initiating free-radical polymerization in an organosiloxane photopolymer doped with a well-characterized distribution of Ag nanoparticles. The self-trapped beam propagates over long distances (≫Rayleigh range) without diverging and permanently inscribes a cylindrical metallodielectric waveguide containing a dispersion of Ag nanoparticles. The self-trapped beam evolves from single-mode to multimode guidance over time; the effects of nanoparticle concentration on multimode dynamics were investigated. These findings open room temperature, soft polymer-based pathways where self-action effects including self-trapping and modulation instability can be exploited to spontaneously generate three-dimensional metallodielectric single or multiple cylindrical waveguides.

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A single-step, room temperature photolithographic route to fabricate periodic metallodielectric microstructures is reported. Ag nanoparticles in organosiloxane sols were first generated through the well-established method of AgCl photoreduction. Evolution of the shape, size and distribution of Ag nanoparticles in the fluid sols upon irradiation with white light was characterised in detail through optical extinction spectroscopy and transmission electron microscopy. Ag nanoparticles were extremely stable in sols, which were subsequently processed into films, gels and monoliths. The application of these composites in the fabrication of optical gratings containing a uniform distribution of Ag nanoparticles was demonstrated through both photomask and interference lithographic techniques. This technique provides accessible routes to a range of metallodielectric microperiodic structures, which could enable experimental verification of theoretically predicted optical properties including enhanced photonic band gaps.

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