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1
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Surface Modification of Metallic Targets with Ultrashort Laser Pulses

100%
Gakovic B., Stasic J., Petrovic S., Radak B., Krmpot A., Jelenkovic B., Trtica M.
Acta Physica Polonica A
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2009
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vol. 116
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issue 4
611-613
EN
Interaction of pulsed femtosecond Ti:sapphire laser (160 fs), operating at high repetition rate (75 MHz) at 800 nm, with nickel-based superalloy Inconel 600 and tungsten-titanium (WTi) target was studied. The WTi target was in form of thin film deposited on silicon substrate. Low laser fluence of maximum 50 mJ/cm^{2} had modified the target surface during irradiation/exposure time of seconds or minutes. The radiation absorbed from the laser beam generates at the surface a series of effects, such as direct material vaporization, formation of clusters, etc. Morphological features of the targets can be summarized as: (a) intensive removal of material and crater appearance; (b) creation of nanostructures; (c) microcracking, etc. Ablation of Inconel 600 surface is effective, resulting in formation of holes with small diameter ( ≤ 10 μm) and relatively large depth ( ≤ 50 μm). In case of WTi target/thin film, the surrounding rim is not so expressed, and crater depths are lower. It can be concluded that the average laser power of the order of watts, pulse energies of the order of nanojoules and high repetition rates (MHz range) can successfully modify metallic materials.
2
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The Influence of Laser Irradiation Time on Fe-Si-C System Structure

100%
Amulevicius A., Daugvila A., Davidonis R., Mazeika K.
Acta Physica Polonica A
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2003
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vol. 104
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issue 6
537-548
EN
The influence of different laser irradiation times on the structure of grey cast iron was studied. Mössbauer spectroscopy and X-ray diffraction were used to characterise the changes caused by laser irradiation. The composition of martensite and austenite as well as the creation of carbide phases during quenching were studied. Modelling of temperature during laser irradiation allowed differences in the influence of different laser irradiation types and times to be explained.
3
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Antibacterial Properties of Polyester Fibres' Materials with Titanium Dioxide Deposited on Their Surface

100%
Karbownik I., Kowalczyk D., Malinowska G., Paruch B.
Acta Physica Polonica A
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2009
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vol. 116
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issue S
S-169-S-171
EN
TiO_{2} particles were deposited onto the surface of polyester (PES) material. The microbiological research were carried out on two bacteria strains: Staphylococcus aureus and Klebsiella pneumoniae, which showed antibacterial properties of the PES surfaces modified with the titanium dioxide under the influence of UV radiation.
4
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Structural Changes in Flash Lamp Annealed Amorphous Si Layers Probed by Slow Positron Implantation Spectroscopy

100%
Anwand W., Schumann T., Brauer G., Skorupa W., Xiong S., Wu C., Gebel T.
Acta Physica Polonica A
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2008
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vol. 113
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issue 5
1273-1278
EN
Flash lamp annealing was applied to the modification of thin amorphous Si layers on SiO_2 and glass. Slow positron implantation spectroscopy was used for the characterisation of the microstructure before and after flash lamp annealing. Changes in the structure down to a depth of some micrometres below the surface observed with slow positron implantation spectroscopy will be presented and discussed.
5
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Laser-PMMA Interaction and Mechanical Stresses

100%
Kovačević A., Srećković M., Gospavić R., Ristić S., Jovanić P.
Acta Physica Polonica A
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2007
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vol. 112
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issue 5
981-986
EN
The polymethylmetacrylate samples were exposed to laser beams of various types of lasers. The modifications of the surfaces of the samples were analyzed by light microscopy and scanning electron microscopy. Numerical approach to thermal distribution for specified power ranges of selected lasers was obtained. The results of polymethylmetacrylate drilling and cutting performed by laser and non-laser means were compared by photoelastic methods.
6
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Models of Interactions of Laser Beams with Materials of Interest for Optical Components and Provoked Damages

100%
Srećković M., Ilić J., Kovačević A., Pantelić S., Latinović Z., Borna N., Ćosović V.
Acta Physica Polonica A
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2007
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vol. 112
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issue 5
935-940
EN
Models of interactions of laser beams with materials of interest for optical components are presented in this paper. Special attention is paid to damages which appear within both active materials and optical components along the path of a propagating beam with theoretical treatment via various models.
7
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Studies of Be-Fe Compounds Synthesized by Laser Irradiation

100%
Amulevicius A., Mazeika K., Sipavicius C., Baltusnikas A.
Acta Physica Polonica A
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2005
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vol. 108
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issue 3
467-478
EN
The FeBe_{2,5,11} compounds and theα-Fe(Be) solid solution of Be_xFe_{1-x} system were synthesized by laser irradiation from a powder mixture. The dependence of the phase structure on the initial sample composition (x=0.1-0.95) was studied. The phases were determined and studied by means of Mössbauer spectroscopy and X-ray diffraction.
8
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Controlling of Optical Band Gap of Allyl Diglycol Carbonate Polymer with Ultraviolet Laser Radiation

100%
Farooq W., Baig M., Fatehmulla A., Al-Salhi M., Al-Ghamdi S., Yakuphanoglu F.
Acta Physica Polonica A
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2013
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vol. 123
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issue 1
106-110
EN
The effects of ultraviolet laser radiation on the structure and optical properties of allyl diglycol carbonate have been investigated. The allyl diglycol carbonate samples were irradiated with 266 nm with different power densities from Nd:YAG laser. The bulk etch rate enhancement and enlargement of track diameter clearly indicate that allyl diglycol carbonate is significantly affected by UV laser. The laser-irradiated allyl diglycol carbonate samples showed a decrease in the optical band gap with increasing laser power density. The obtained results indicate that the optical band gap of the alpha irradiated polymer is varied from 4.10 eV to 2.65 eV by UV laser irradiation.
9
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Laser Interaction with Material - Theory, Experiments and Discrepancies

88%
Srećković M., Ilić J., Davidović M., Djokić B., Tomić Ž., Latinović Z., Družijanić D.
Acta Physica Polonica A
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2009
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vol. 116
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issue 4
618-621
EN
The experimental treatment of chosen material with laser beams, starting from continuous wave up to fs pulses, produces the necessity to find the common and sophisticated theoretical approaches to interaction modeling. For chosen materials, some laser treatment and damage analyses are performed. The provoked stresses and parameters of transport processes (penetration depth) are calculated by using the programs for electrical circuit analyses. Some inconsistencies in the treatment of large area laser-material interaction are discussed.
10
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Nanostructure of Si-Ge Near-Surface Layers Produced by Ion Implantation and Laser Annealing

88%
Klinger D., Kret S., Auleytner J., Żymierska D.
Acta Physica Polonica A
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2002
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vol. 102
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issue 2
259-264
EN
An annealing with the nanosecond laser light pulse is applied for crystal lattice reconstruction of a disturbed near-surface layer, which was created in semiconductor material as a result of the implantation process. Radiation with energy density higher than the threshold value causes the melting of the surface layer and then the epitaxial recrystallization from the melt on a different substrate. Structural changes occurring in the Ge implanted Si crystals after annealing with different energy densities are investigated by means of the cross-section high-resolution transmission electron microscopy.
11
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Induced Absorption in Gadolinium Gallium Garnet Irradiated by High Energy ^{235}U Ions

88%
Potera P., Ubizskii S., Sugak D., Schwartz K.
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EN
The present work is devoted to investigation of optical absorption in pure Gd_{3}Ga_{5}O_{12} (GGG) single crystals in the spectral range 0.2-1.1 μm induced under influence of the ^{235}U ions irradiation with energy 2640 MeV and a fluence 10^{9}-10^{11} cm^{-2}. The induced absorption for 10^{9} cm^{-2} is caused by recharging of point defects, both growth ones and impurities. After irradiation by ^{235}U ions with fluences starting from 3 × 10^{9} cm^{-2} the absorption rise is probably caused by contribution of the lattice destroying as a result of heavy ion bombardment as well as radiation displacement defects.
12
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The Influence of Fiber Laser Pulse Processing on Coercivity and Nanohardness of Fe-3.2Si Grain-Oriented Electrical Steel in relation with its Surface Changes and Magnetic Domains Modifications

75%
Puchý V., Falat L., Kováč F., Petryshynets I., Džunda R., Šebek M.
Acta Physica Polonica A
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2017
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vol. 131
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issue 6
1445-1449
EN
Fiber laser scribing of Fe-3.2Si grain-oriented electrical steel was carried out using three different laser pulse regimes, namely a single pulse laser regime, multipulse laser regime and multipulse laser regime with modulation of laser pulses. The samples were tested for coercivity and nanohardness before and after laser processing. Clear improvements in soft magnetic characteristics were observed for all the regimes using the lowest single pulse energy of 0.6 mJ. The best improvement i.e. the most significant decrease in coercivity was obtained after the regime with 5 pulses. Further increasing in both pulse energy and pulse number resulted only in detrimental effects on both magnetic and mechanical characteristics. Introduction of 50 kHz pulse modulation within 100-pulse laser regimes resulted in lower coercivity values in comparison with the same regimes without modulation. The major effects responsible for the observed improvement are related to optimal refinement and rearrangement of magnetic domains determined by the balance of laser-induced residual stresses and plastic deformation at the surface of the treated material. Thus the fiber laser pulse processing has been recognised as a useful and energy efficient tool in obtaining electrical steels for power transformers with lower core losses.
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