Marian Rusek

Cluster explosion in an intense laser pulse

Abstract This manuscript addresses a hot topic in the field of cluster physics: the explosion of rare-gas atomic clusters induced by short, intense laser pulses. Within the Thomas–Fermi model we have developed an numerical approach for an explicitly time-dependent description of small to medium size clusters in 3D. Such an approach, though strongly simplified in comparison to fully quantum-mechanical schemes, is nevertheless expected to yield a qualitatively correct description of the electronic and ionic dynamics of these systems, at a much lower computational cost.

Anderson Localization of Electromagnetic Waves in Confined Disordered Dielectric Media

Scattering of electromagnetic waves from various kinds of obstacles is rich of interesting and sometimes unexpected phenomena. Already for two scatterers placed together well within a wavelength an extremely narrow proximity resonance can appear [10]. For many randomly distributed scatters we may expect that, for same range of parameters, Anderson localization can show up.

From Proximity Resonances to Anderson Localization

This paper serves as a guide for a tour from proximity resonances to Anderson localization. It can be quite a long trip. To see a proximity resonance it is enough to have just two scatteres placed very close together. To observe Anderson localization we need, in general, an infinite number of scatterers. It is hard to count from two to infinity within ten pages. Therefore we will have to stop somewhere in between. We are able to manage 1000 scatterers and, fortunately, this number seems to be large enough to justify some reasonable conclusions.

Bands of Localized Electromagnetic Waves in 3D Random Media

Anderson localization of electromagnetic waves in three-dimensional disordered dielectric structures is studied using a simple yet realistic theoretical model. An effective approach based on analysis of probability distributions, not averages, is developed. The disordered dielectric medium is modeled by a system of randomly distributed electric dipoles. Spectra of certain random matrices are investigated and the possibility of appearance of the continuous band of localized waves emerging in the limit of an infinite medium is indicated. It is shown that localization could be achieved without tuning the frequency of monochromatic electromagnetic waves to match the internal (Mie-type) resonances of individual scatterers. A possible explanation for the lack of experimental evidence for strong localization in 3D as well as suggestions how to make localization experimentally feasible are also given. Rather peculiar requirements for setting in localization in 3D as compared to 2D are indicated.

Localization of Electromagnetic Waves in 2D Random Media

Recently random dielectric structures with typical length scale matching the wavelength of electromagnetic radiation in the microwave and optical part of the spectrum have attracted much attention. Propagation of electromagnetic waves in these structures resembles the properties of electrons in disordered semiconductors. Therefore many ideas concerning transport properties of light and microwaves in such media exploit the theoretical methods and concepts of solid-state physics that were developed over many decades. One of them is the concept of electron localization in noncrystalline systems such as amorphous semiconductors or disordered insulators. As shown by Anderson1, in a sufficiently disordered infinite material an entire band of electronic states can be spatially localized. Thus for any energy from this band the stationary solution of the Schrodinger equation is localized for almost any realization of the random potential. Prior to the work due to Anderson, it was believed that electronic states in infinite media are either extended, by analogy with the Bloch picture for crystalline solids, or are trapped around isolated spatial regions such as surfaces and impurities2.