Nonlinear optical properties of artificial dielectrics in the nano-scale

Artificial dielectrics constitute a class of man-made materials; the effective permittivity and permeability of a given dielectric material are altered by embedding small clusters of another material, typically nano-size metal clusters. Additional dielectric properties are achieved as a result of local interactions between the material components. Such composition was used over many centuries as a method to stain glass: in the case of gold-embedded glass, the result is a red, winelike color. This concept was extended to include nano-size semiconductor embedded dielectrics, conditional artificial dielectrics,¹ to emphasize the dependence on control parameters such as light. It is tempting to take this concept one step further and attempt to alter the capacitance and inductance of dielectric materials by geometrical means. Such features should be of sizes much smaller than the propagating electromagnetic wavelength to give the material new effective properties.² For example, ordered arrays of nano-size spheres offer a practical route to develop periodic nanostructures on a sub-wavelength scale; by using these structures as templates for other, nonlinear materials, one opts to achieve novel optical characteristics.