Modelling of photonic band gap structures

In a novel class of engineered dielectric materials, known as photonic crystals or photonic band gap materials new electromagnetic effects can be obtained. The light localization is a particular interesting phenomenon of a great importance for using optical waves in information and telecommunication technologies. Because of the periodic spatial character of the dielectric constant this kind of structures have completeIy merent characteristics than uniform materials. A part of the formation of pass bands and band gaps of eigenfrequenaes, extremely small group velocity can be easily obtained in a photonic crystals. By considering the photonic band structure described as a function of the wave vector k of a lD, 2D or 3D lattice, it is possible to find that there are points where group velocity is equal to zero. This group velocity anomaly is peculiar to 2D and 3D photonic crystals. Using this phenomenon a lot of prototypal devices based on photonic crystals can be designed and constructed.