New design for optical filters based on photonic crystals
Résumé
Nowaday, photonic crystals appear to be challenging materials to observe and investigate the electromagnetic wave propagation with respect to the one dimensional (1d) Anderson localization. Such structures with spatially modulated dielectric properties attract an ever growing interest for technological aspects. Here, we consider a 1d photonic crystal with a period d in the z direction. Thin films of a dielectric material embedded between vacuum are regularly reproduced along N periods. Each element of the unit cell is characterized with its dielectric material constant and layer thickness a respectively. The propagation of electromagnetic waves is then examined by means the transfer matrix formalism. A theoretical formalism is formulated throughout the light equation propagation in a 1d photonic crystal. In particular the presence of correlation in disorder in the sample, it is shown the suppression of localization . This spectacular phenomenon is related to the short range intentionally binary disorder which induces resonances into the spectrum breaking down the Anderson localization. By properly adjusting the intrinsic dimer unit cell parameter i.e. dimer dielectric constants εd, light can be transmitted with a very large localization length ξ through a ballistic canal, opening up new possibilities in tailoring optical filter. Moreover with increasing the degree of disorder, via the dimer concentration cd and the period number N, the quality in transmitting light around the resonance is improved. On this basis, the conception of new class of devices based on these peculiar results and their physical implications on the propagation properties may be suggested