N. M. Makarov

Nonlocal effects in the electrodynamics of metallic slabs

The influence of spatial dispersion and size on the interaction of a metallic slab with electromagnetic radiation has been studied in the model of the Boltzmann kinetic equation. It has been shown that the results are qualitatively different from those obtained in the Drude-Lorentz approximation. In particular, in the high-frequency region, the absorption oscillates with the radiation frequency and sample thickness. The absorption becomes sensitive to the Fermi velocity of electrons and depends nontrivially on the electron relaxation rate. The results may be useful for the analysis of the electromagnetic response of metal-dielectric micro- and nanostructures in the terahertz and/or infrared frequency range.

One dimensional Kronig-Penney model with positional disorder: Theory versus experiment

We study the effects of random positional disorder in the transmission of waves in the one-dimensional Kronig-Penny model formed by two alternating dielectric slabs. Numerical simulations and experimental data revealed that the so-called resonance bands survive even for relatively strong disorder and large number of cells, while the nonresonance bands disappear already for weak disorder. For weak disorder we derive an analytical expression for the localization length and relate it to the transmission coefficient for finite samples. The obtained results describe very well the experimental frequency dependence of the transmission in a microwave realization of the model. Our results can be applied both to photonic crystals and semiconductor superlattices.

Generation of correlated binary sequences from white noise

We suggest a method for generation of random binary sequences with prescribed correlation properties. It is based on a kind of modification of the widely used convolution method of constructing continuous random processes. Apart from the theoretical interest, this method can be used in various applications such as the design of one-dimensional devices giving rise to selective transport properties.

Microwave realization of quasi-one-dimensional systems with correlated disorder

(Received 3 December 2010; revised manuscript received 3 February 2011; published 12 April 2011)A microwave setup for mode-resolved transport measurement in quasi-one-dimensional (quasi-1D) structuresis presented. We will demonstrate a technique for direct measurement of the Green’s function of the system.With its help we will investigate quasi-1D structures with various types of disorder. We will focus on stratifiedstructures,i.e.,structuresthatarehomogeneousperpendiculartothedirectionofwavepropagation.Inthiscasetheinteraction between different channels is absent, so wave propagation occurs individually in each open channel.We will apply analytical results developed in the theory of one-dimensional (1D) disordered models in order toexplain main features of the transport. The main focus will be selective transport due to long-range correlationsin the disorder. In our setup, we can intentionally introduce correlations by changing the positions of periodicallyspaced brass bars of finite thickness. Because of the equivalence of the stationary Schr¨odinger equation and theHelmholtz equation, the result can be directly applied to selective electron transport in nanowires, nanostripes,and superlattices.DOI: 10.1103/PhysRevB.83.134203 PACS number(s): 72

Non-conventional Anderson localization in bilayered structures

We resolve the problem of non-conventional Anderson localization emerging in bilayered periodic-on-average structures with alternating layers of materials with positive and negative refraction indices. Recently, it was numerically discovered that in such structures with weak fluctuations of refractive indices, the localization length Lloc can be enormously large for small wave frequencies ?. Within a new approach allowing us to go beyond the second order of perturbation theory, we derive the expression for Lloc valid for any ? and small variance of disorder, ?21. In the limit ??0 one gets a quite specific dependence, L?1loc??4?8. Our approach allows one to establish the conditions under which this effect occurs.

Enhanced transmission of terahertz radiation through a periodically modulated slab of layered superconductor

We predict the enhanced transparency of a modulated slab of layered superconductor for terahertz radiation due to the diffraction of an incident wave and the resonance excitation of eigenmodes. The electromagnetic field is transferred from the irradiated side of the slab to the other by excited waveguide modes (WGMs) which do not decay in layered superconductors, in contrast to metals, where the enhanced light transmission is caused by the excitation of evanescent surface waves. We show that a series of resonance peaks can be observed in the dependence of transmittance on the incidence angle when the dispersion curve of the diffracted wave crosses successive dispersion curves for the WGMs.

Anderson localization in bi-layer array with compositional disorder: Conventional photonic crystals versus metamaterials

The localization length has been derived for one-dimensional bi-layered structures with random perturbations in the refractive indices for each type of layers. Main attention is paid to the comparison between conventional materials and those consisting of mixed right-hand and left-hand materials. It is shown that the localization length is described by the universal expression for both cases. The analytical results are confirmed by numerical simulations.

Nonlocal effect on optic spectrum of a periodic dielectric-metal stack

On the basis of the formalism of the Boltzmann kinetic equation for the distribution function of the conduction electrons, the photonic band structure of binary dielectric-metal superlattice is theoretically studied. Using the constitutive nonlocal relation between the electrical current density and the electric field inside the metallic layer, the dispersion equation for photonic eigenmodes in the periodic stack is analytically expressed in terms of the surface impedances at the interfaces of the metal and dielectric layers. In the case of very thin metallic layers, the optic spectrum for the superlattice exhibits narrow pass bands as a result of the strong contrast between the impedances of the dielectric and the metal. The narrow pass bands are attributed to Fabry-Perot resonances in the relatively-thick dielectric layer. The metal nonlocality is well pronounced in the infrared and, therefore, the nonlocal effect upon the photonic band structure of the superlattice can be strong when the Fabry-Perot resonance bands are in that frequency range. Our results for the photonic spectrum have been compared with those obtained within the local Drude-Lorentz model. Noticeably differences not only in the the magnitude, but also in the sign of the real part of the Bloch wave number in the Fabry-Perot resonance bands, have been found.

Landau damping of electromagnetic transport via dielectric–metal superlattices

We discuss the propagation of electromagnetic waves through a one-dimensional periodic array of bilayers with metal inclusions. We show that the nonlocality of metal conductivity leads to the emergence of the fundamental collisionless Landau damping. It cannot be neglected, not only when prevailing over ordinary collision damping, but even when these two kinds of electromagnetic absorption are of the same order. Landau damping always exists and considerably alters the photonic transmission of the array within the THz and near-infrared frequency range.

THz photonic bands of periodic stacks composed of resonant dielectric and nonlocal metal

The photonic band structures of superlattices composed of spatially-dispersive metal and polaritonic dielectric are theoretically investigated. The nonlocal relation between the electric current density and the electric field inside the metal layers is defined within the formalism of the Boltzmann kinetic equation, whereas the frequency dependent permittivity of the polar layers is modeled by a Lorentz-oscillator. Due to the large dielectric contrast between metal and polar components, the photonic band structure exhibits flat pass bands associated with Fabry-Perot resonances in the dielectric layers. There is also a wide stop band because of the existence of the polaritonic gap. We have compared our results with the predictions of the Drude-Lorentz model for the frequency-dependent metal permittivity. It is found that the nonlocal effect on the Fabry-Perot resonance bands is strong if their corresponding frequencies are within the interval where the difference between the impedances at both metal surfaces, predicted by the nonlocal and local formalisms, is maximal.