Laser interactions with bundle fiber structures

Laser damages of materials are in research focus during the last decade. These terms can be understood as useful in the treatment of materials or in theoretical modeling of interactions of laser beams with the material. Also, they can be destructive when it comes to high power density where the nonlinear effects are present, too. In addition to the theory, many detailed experimental work is required for new optical components applications. The experiments with Nd 3+ : YAG laser (1.064 µm) with defined working regime and power densities and specifically developed optical fiber bundles are the subject of this paper. The fibers are developed in laboratory conditions for specific purposes. Also, commercial optical fiber bundle for dental use are presented and discussed as comparison with the same laser types

Influence of nuclear radiation and laser beams on optical fibers and components

The influence of nuclear radiation and particles has been the object of investigation for a long time. For new materials and systems the research should be continued. Human activities in various environments, including space, call for more detailed research. The role of fibers in contemporary communications, medicine, and industry increases. Fibers, their connections and fused optics components have one type of tasks - the transmission of information and power. The other type of tasks is reserved for fiber lasers: quantum generators and amplifiers. The third type of tasks is for fiber sensors, including high energy nuclear physics. In this paper we present some chosen topics in the mentioned areas as well as our experiments with nuclear radiation and laser beams to fiber and bulk materials of various nature (glass, polymer, metallic, etc.)

Special Issue on Atomic and Ionic Collisions with Formation of Quasimolecules

Many areas of science today, like atomic and molecular physics, nuclear physics, astrophysics, laboratory plasma research etc., depend on data for ionic, atomic, and molecular collision processes. The purpose of the Special Issue “Atomic and Ionic Collisions with Formation of Quasimolecules” in Atoms is to engage a broad community of researchers to consolidate knowledge, make new discoveries, and to continue the exchange of ideas

Contemporary problems in experiments, theory and application of interest in ecology with lasers in laboratory and remote detection

Multiple sensor systems and applications in ecology deserve multidisciplinary approach. Concerning laser implementation in monitoring, main parameters and processes have to be chosen in description of object of interest. The purpose of this paper is to underline the links and usability of scattering matrices in the description of biological objects (cells, nuclei, bacteria, etc). Light scattering processes are unavoidable in application and measurements, based on laser systems. Depending on the measurement systems, angular scattering and differential cross sections carry valuable information, and measurements should confirm chosen simplifications from theory. Shape recognition, size and chemical content could be certainly of interest in one part of ecological monitoring (water). Thermal imaging of objects depends on emissivity (water, ground, etc.) and some simplifications of derived cases are added to the previous

Contemporary problems in experiments, theory and application of interest in ecology with lasers in laboratory and remote detection

Multiple sensor systems and applications in ecology deserve multidisciplinary approach. Concerning laser implementation in monitoring, main parameters and processes have to be chosen in description of object of interest. The purpose of this paper is to underline the links and usability of scattering matrices in the description of biological objects (cells, nuclei, bacteria, etc). Light scattering processes are unavoidable in application and measurements, based on laser systems. Depending on the measurement systems, angular scattering and differential cross sections carry valuable information, and measurements should confirm chosen simplifications from theory. Shape recognition, size and chemical content could be certainly of interest in one part of ecological monitoring (water). Thermal imaging of objects depends on emissivity (water, ground, etc.) and some simplifications of derived cases are added to the previous

Free-Free Absorption in Solar Atmosphere

International audienceThe free-free i.e. electron-ion inverse "Bremsstrahlung" characteristicsare determined for the case of the solar atmosphere as well as solarinterior where such plasma characteristics as plasma density andtemperature change in wide region. We demonstrate that determination ofthese characteristics such as the absorption coefficients and Gauntfactors can be successfully performed in the whole diapason of electrondensities and temperatures which is relevant for the correspondingatmosphere model. The used quantum mechanical method of the calculationof the corresponding spectral absorption coefficient and Gaunt factor isdescribed and discussed in details. The results are obtained for thecase of a solar photosphere and solar interior model in the wavelengthregion 10{nm} ?slant ? ?slant 3000{nm}. The range of the physicalparameters covers the area important for plasma modeling fromastrophysical standpoint (white dwarfs, central stars of planetarynebulae, etc). Also, these results can be of interest and use ininvestigation of different laboratory plasmas

Dynamic Instability of Rydberg Atomic Complexes

Atoms and molecules in highly excited (Rydberg) states have a number of unique characteristics due to the strong dependence of their properties on the values of principal quantum numbers. The paper discusses the results of an investigation of collisional Rydberg complexes specific features, resulting in the development of dynamic chaos and the accompanying diffusion autoionization processes. It is shown (experiment and theory) that, in subthermal low energies, the global chaotic regime that evolved in quasimolecular systems leads to significant changes in the Rydberg gases radiation/ionization kinetics. The effect of Förster resonance on the width of the fluorescence spectra and stochastic ionization processes in Rydberg systems is also discussed

Free–free absorption coefficients and Gaunt factors for dense hydrogen-like stellar plasma

International audienc

The Collisional Atomic Processes of Rydberg Hydrogen and Helium Atoms: Astrophysical Relevance

Elementary processes in astrophysical environments traditionally attract researchers’ attention. We present the data needed for the inclusion of the specific atomic collisional processes in the investigation of the optical and kinetic properties of weakly ionized stellar atmosphere layers. The first type of processes are collisional ionisation (chemi-ionization) processes, and the second ones are excitation and de-excitation (i.e., (n-n′)-mixing processes). We give the rate coefficients of the aforementioned processes for the conditions that exist in the solar photosphere, the atmosphere of DB white dwarfs, M-type red dwarfs, etc