Nano-structuring for enhanced glass composites
Glass-metal nanocomposites combine a host of benefits for architecting innovative materials for photonics and optoelectronics applications. In addition to their resonance in the visible and near-infrared, they demonstrate very fast and strong optical non-linear response. Compatibility with photonic and electronic circuits is also facilitating exploitation in various technological applications. Within the context of NANOCOM (Nanostructured composite materials), researchers employed nano-structuring of glassy composites to develop innovative materials for photonics. Activities included modelling, fabrication and characterisation of submicron patterned nanocomposites, fabrication of bimetallic glass-metal nanocomposites and modification with electric fields. Researchers first developed models describing physical and chemical processes occurring in the formation of glass-metal nanocomposites. These accurately provided a quantitative description of the reactive diffusion of reducible metals and of reducing agents (hydrogen) in glasses. After successfully fabricating bimetallic glass-metal nanocomposites using copper and silver, the team noticed that copper nanoparticles were formed closer to the glass slab surface than silver. This enables design of layered structures with submicron periodicity for use in all-optical devices. Alongside experimentally demonstrating the theory of electric field-assisted dissolution (EFAD) that causes glass modification and nano-patterning, researchers also developed relative models describing glass behaviour. Findings open up new avenues toward using glass to fabricate photonic and optoelectronic components. Formation of metal island films on the glass surface was exploited to fabricate 1D and 2D gratings by poling the glass with a nano-structured glassy carbon electrode. Results are useful for developing sensing and plasmonic devices. In addition, researchers demonstrated that non-linear response can be engineered by varying nanoparticle size. Team members developed three different approaches, including EFAD for fabricating glass-metal nanophotonic components. They showed that these nano-structuring techniques can be used to produce structures as small as 150 nm with varied birefringence and dichroism. These techniques were then used to form 1D and 2D diffraction gratings. Gratings formed by reactive ion etching demonstrated the capability of controlling the structure's non-linear response. This result will prove useful for future photonic and non-linear optical devices that rely on (reverse) saturable absorption in certain spectral ranges. NANOCOM's newly developed nanocomposite materials can broaden functionality of future photonic components. Project results were disseminated through 36 publications in peer-reviewed journals and at 50 conferences.
Keywords
Nano-structuring, glass-metal nanocomposites, photonics, optoelectronics, plasmonic devices
