EM wave propagation in a one-dimensional layered medium: disorder effects

Abstract

The authors show, using simple experiments and calculations, the effect of disorder on the propagation of a plane electromagnetic wave in a one-dimensional layered medium with a negligible dissipation. They give experimental evidence of the phenomenon of Anderson localisation. Also the disordered medium finite-size effect is demonstrated. When the medium is periodic, one recovers the pass and forbidden bands of solid state physics. When the medium is disordered, even a small number of layers can produce a drastic attenuation of the wave transmission. For a high degree of disorder, the experimental estimation of the localisation lengths are comparable with theoretical predictions. Since in even the most disordered medium, the localisation length is of the same order as the length of the experimental medium they observe fluctuations of the transmission coefficient from sample to sample. This is associated with the appearance of resonant modes due to disorder which are observed experimentally and predicted numerically.