Journal of Russian Laser Research, Volume 31, Number 4, 2010 ANOMALIES OF LIGHT TRANSMISSION IN STRUCTURALLY ORDERED NANOCOMPOSITES Alexander S. Shalin and Vladimir S. Gorelik P. N. Lebedev Physical Institute, Russian Academy of Sciences Leninskii Prospect 53, Moscow 119991, Russia ∗ Corresponding author e-mail: gorelik @ sci.lebedev.ru Abstract We study the optical properties of spatially ordered nanocomposites consisting of spherical nanopar- ticles. Based on the integral equation method, we derive and investigate the expressions for the fields inside and outside the system. We show that two different states of the system possibly depend on the material and geometric parameters of the nanoaggregate. The states differ by the presence or absence of the forbidden band (an interference reflection peak) in the visible range for photons of definite energy. In the case of dielectric nanoparticles, we show that, if the nanoaggregate is not a photonic crystal in the visible wavelength range, scattering of light by the particles is suppressed in the nanostructure with definite parameters, and the ensemble under study becomes completely trans- parent. We propose a composite material, which possesses a 100% transmission at some wavelengths and is formed by densely packed dielectric nanospheres. We study the light transmission through an aggregate consisting of metal (gold) nanoclusters and find that, in spite of the fact that absorption is an intrinsic characteristic of metals, in a definite region of the near-IR range of the spectrum, this system is also characterized by an anomalously high transmission of radiation (close to 100%). Keywords: nanostructure, transmission, forbidden band, light, photonic crystal, field, polarizability, monolayer, lattice sum. 1. Introduction At present the optical properties of artificial materials consisting of various kinds of nanosize objects embedded into a medium and arranged in a certain spatial manner are of a special interest. Such artificial materials are called metamaterials [1–4], and in some of them foreign objects are characterized by a size of ∼1–100 nm. A particular case of metamaterials are photonic crystals. In photonic crystals, foreign objects are arranged in the carrying medium periodically (in the form of a crystal lattice). Recently, photonic crystals whose lattice constants are comparable with the wavelength of visible or ultraviolet radiation have attracted a lot of attention. This interest arises from the possibility of implementing a number of new effects in photonic crystals owing to the periodic micro- or nanostructure of the medium, as well as to the specific scattering of light by foreign nanoparticles present in photonic crystals. In particular, varying the dielectric and geometric parameters of the system, it becomes possible to produce media with giant, superlow, and negative refractive indices [1, 5, 6], as well as with a refractive index whose real part is close to unity [7]. 390 Translated from a manuscript submitted first on January 18, 2010 and in final form on June 10, 2010. 1071-2836/10/3104-0390 c  2010 Springer Science+Business Media, Inc.