Superlensing effect in liquid surface waves.

We present experimental observations and numerical simulations of superlensing effect in liquid surface waves. We use rigid cylinders to create a two-dimensional periodic lattice, in which liquid surface waves propagate. Through the observation of a superlensing effect, we demonstrate the existence of negative refraction in surface waves.

Complete band gaps for liquid surface waves propagating over a periodically drilled bottom.

A plane-wave expansion approach is developed to solve the mild-slope equation for liquid surface waves propagating over a bottom with periodic structures. Band structures are calculated for the bottom periodically drilled with the square or triangular lattice of holes. Complete band gaps are found for both lattices.

Coloration strategies in peacock feathers.

We report the mechanism of color production in peacock feathers. We find that the cortex in differently colored barbules, which contains a 2D photonic-crystal structure, is responsible for coloration. Simulations reveal that the photonic-crystal structure possesses a partial photonic bandgap along the direction normal to the cortex surface, for frequencies within which light is strongly reflected.

Band structures and band gaps of liquid surface waves propagating through an infinite array of cylinders.

The multiple scattering method is applied to the calculations of band structures of liquid surface waves propagating through an infinite array of vertical cylinders. The influence of the filling fraction on the formation of band gaps is discussed. It is found that there exist complete band gaps for both the square and triangular arrays of cylinders.