L’optique des milieux désordonnés corrélés est un sujet de recherche conceptuellement riche à l’interface entre la physique des ondes dans les milieux complexes et la nanophotonique. Les études récentes démontrent le fort potentiel de l’ingénierie du désordre dans de nombreuses applications, notamment la conception de l’apparence visuelle. Cet article de synthèse examine les fondements théoriques, les techniques expérimentales et les principaux résultats obtenus dans l’étude de l’interaction de la lumière avec le désordre corrélé, et identifie les principaux défis à relever dans un avenir proche.
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Early achievements and applications of correlated disordered media in optics and photonics. (a) Male mandrill (Mandrillus sphinx) blue facial skin and cross section of its dermis in a structurally colored area that reveals parallel collagen fibers organized in a correlated array. Adapted from Prum and Torres, 2004. (b) Modified light transport (described by the inverse transport mean free path 1=lt) produced by engineering short-range structural correlations thanks to Coulomb repulsion between charged particles (the filled symbols and solid line). Hard-sphere systems (open symbols and dotted line) exhibit weaker correlations. The dashed line is a model neglecting completely structural correlations. Adapted from Rojas-Ochoa et al., 2004. (c) Anomalous light transport in L´evy glasses. A fractal heterogeneity is engineered by adding transparent spheres with sizes varying over orders of magnitude in a host matrix. Transport can be modeled using a truncated L´evy walk. On finite-size samples, this leads to an anomalous scaling of the total transmittance T ∼ L−α=2 (experiments shown as symbols; lines are fits). Adapted from Barthelemy, Bertolotti, and Wiersma, 2008. (d) Light localization in randomly perturbed inverse opal photonic crystals (upper left inset). Simulations reveal spatially localized modes near the photonic band edge (lower left inset). Their typical spatial extent (the localization length ξ) depends strongly on the degree of disorder. Adapted from Conti and Fratalocchi, 2008. (e) Existence of photonic gaps in amorphous photonic materials. Simulations of the spectral density (a quantity proportional to the density of states) in a connected amorphous diamond structure exhibiting short-range order shows a photonic gap near d=λ ≃ 0.23, where d is the average bond length. Adapted from Edagawa, Kanoko, and Notomi, 2008. (f) Random lasing in two-dimensional photonic structures with correlated disorder. Short-range correlations are shown to increase the lasing efficiency at certain frequencies due to enhanced optical confinement. Adapted from Noh et al., 2011.