Molding Fluorescence Light by Photonic Crystals and Fractal Structures

The properties of electromagnetic waves are known to be modified by interactions with periodic and aperiodic structures. Photonic crystals made of a periodic array of dielectric materials, e.g. colloidal spheres, have been studied intensively in terms of formation of photonic bandgaps, localization of light and control of spontaneous emission. Bandgap engineering is expected to bring a variety of optical device applications such as narrow-band filters and lowthreshold lasers. Another promising way to modify properties of light is by using the discrete and singular photon density of states within self-similar (fractal) structures. Results reviewed here clearly show that the unique optical properties of fractal structures offer large opportunities for designing new optical materials. The present review focuses on recently reported publications & patents on the molding of fluorescence light by photonic crystals and fractal structures respectively as well as their possible applications in future. With this review we want particularly to stimulate more interest in research on optical properties of fractal structures obtainable by different chemical and physical procedures.