3. Some examples of potential applications for photonic crystals

The bandgap, diffraction, refraction, filtering and guiding properties of photonic crystals are not specific to a particular wavelength range. The only things that obviously change from one domain to another are the length scales involved, the technical implementation aspects and the intrinsic properties of the materials that make up the crystal. This observation of "universality" explains the important research dynamic that has been created around photonic crystals, bringing together electromagneticians, opticians and solid-state physicists. The same diversity can be found in the range of applications for photonic crystals, with broad spectral coverage from the microwave to the visible range. Here, we present just three of the most representative potential applications of photonic crystals:

• high-impedance surfaces ;

• ...