Quasicrystal formation in binary soft matter mixtures

Using a strategy that may be applied in theory or in experiments, we identify the regime in which a model binary soft matter mixture forms quasicrystals. The system is described using classical density functional theory combined with integral equation theory. Quasicrystal formation requires particle ordering with two characteristic lengthscales in certain particular ratios. How the lengthscales are related to the form of the pair interactions is reasonably well understood for one component systems, but less is known for mixtures. In our model mixture of big and small colloids confined to an interface, the two lengthscales stem from the range of the interactions between pairs of big particles and from the cross big-small interactions, respectively. The small-small lengthscale is not significant. Our strategy for finding quasicrystals involves tuning locations of maxima in the dispersion relation, or equivalently in the liquid state partial static structure factors

Nonlinear Metamaterials

Metamaterials are engineered structures designed to exhibit exotic electromagnetic properties. Early on in the development of metamaterials, these properties were extended to exotic regimes of nonlinear behaviour, unknown in classical nonlinear optics. In this chapter, we give a historical overview of metamaterials, considering first their exotic linear properties, and show how these give rise to exotic nonlinear properties, at frequency ranges from RF to visible. We overview the main attractive features of metamaterials for nonlinear applications, namely their strong local field enhancement, their ability to achieve exotic phase matching conditions, and the possibility to create inclusions with the correct symmetry to enhance a chosen nonlinear process. We then summarise the two most important classes of nonlinear optical metamaterials, plasmonic and all-dielectric