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Laser-controlled modifications of the structure and topology of the surface layers of a solid that are used to obtain specific characteristics in objects for various purposes are considered. Structural phase transitions induced in a solid by laser radiation are analyzed, depending on the size of nanoparticles (nanoclusters). The propagation of surface states is modeled in the context of the diffusion model and cellular automata.

We report on the fabrication of fractal dendrites using laser-induced melting of aluminum alloys. We target boron carbide (B4C), which is one of the most effective radiation-absorbing materials characterized by a low coefficient of thermal expansion. Due to the high fragility of B4C crystals, we were able to introduce its nanoparticles into a stabilization aluminum matrix of AA385.0. The high-intensity laser field action led to the formation of composite dendrite structures under the effect of local surface melting. Modelling the dendrite cluster growth confirms its fractal nature and sheds light on the pattern behavior of the resulting quasicrystal structure.

The conductivity of thin films composed by clusters of gold and silver nanoparticles has been studies in a wide range of temperatures. The switch from a temperature independence to an exponential thermal dependence of the conductivity manifests the crossover between the tunnel and thermally activated hopping regimes of the electronic transport at the temperature of 60 °C. The characteristic thermal activation energy that governs hopping of electrons between nanoparticles is estimated as 1.3 eV. We have achieved a good control of the composition and thicknesses of nano-cluster films by use of the laser ablation method in colloidal solutions.

Metal–carbon materials exhibiting surface-enhanced Raman scattering have been synthesized by laser irradiation of colloidal systems consisting of carbon and noble metal nanoparticles. The dependence of the Raman scattering intensity on the material composition and laser irradiation conditions has been investigated. The possibility of recording the Raman spectrum of organic dye rhodamine 6G, deposited in amount of 10–6 M on the substrate obtained from a colloidal solution is demonstrated.

A method is proposed for the synthesis of linear carbon chains under irradiation of colloidal systems consisting of schungite nanoparticles by an ytterbium fibre laser with a pulse duration of 100 ns and an energy up to 1 mJ. Colloidal systems have been previously prepared by laser ablation of a schungite target in distilled water using a Nd3+ : YAG laser with a pulse duration of 1 ms and an energy up to 10 J.

The results from experiments on the laser irradiation of metallic targets of the copper group immersed in liquid are reported. Comparative studies of the formation of colloids during the laser irradiation of targets with varying (from moderate to ultrahigh) radiation intensities are conducted. The dependence of the size of obtained particles on laser irradiation conditions (pulse duration and radiation intensity) is revealed.

We experimentally realize nano-antennas based on hybrid silicon-gold nanoparticles (NPs). The silicon particles covered by clusters of small metal NPs are fabricated from a liquid phase under the effect of the laser irradiation. The complex nanoclusters containing both Si and Au components provide the enhancement of the near-field intensity and the resonant light scattering associated with excitation of multipole resonances in NPs. A strong sensitivity of the resonant light absorption to the hybrid particle size and material parameters is experimentally documented and theoretically discussed. The results demonstrate a high potentiality of the hybrid NPs for the realization of functional optical devices and metasurfaces.

We studied monoatomic linear carbon chains stabilised by gold nanoparticles attached to their ends and deposited on a solid substrate. We observe spectral features of straight chains containing from 8 to 24 atoms. Low temperature PL spectra reveal characteristic triplet fine-structures that repeat themselves for carbon chains of different lengths. The triplet is invariably composed of a sharp intense peak accompanied by two broader satellites situated 15 and 40 meV below the main peak. We interpret these resonances as an edge-state neutral exciton, positively and negatively charged trions, respectively. The time-resolved PL shows that the radiative lifetime of the observed quasiparticles is about 1 ns, and it increases with the increase of the length of the chain. At high temperatures a non-radiative exciton decay channel appears due to the thermal hopping of carriers between parallel carbon chains. Excitons in carbon chains possess large oscillator strengths and extremely low inhomogeneous broadenings., Comment: 23 pages, 5 figures

The stable dispersions of the hybrid shungite carbon (ShC)–Me(Ag, Au) nanoparticles were produced in water dispersions of ShC nanoparticles and corresponding metals affected by laser impulses of various durations. Films, occurring as periodic structures that contain graphene-like carbon without a hydration constituent, are formed upon condensation of such dispersions

The formation of hybrid silicon-gold NPs as a result of the laser action on a mixed colloidal solution is observed. These hybrid NPs are characterized by the amplification and broadening of the near-field photoluminescence spectra compared to pure silicon NPs. A strong sensitivity of the spectral shape of the emitted light to the intensity of the exciting white light is documented. These results may be used for the realization of functional metasurfaces consisting of randomly distributed resonant NPs. Moreover, as the synthesized NPs emit in red, green and yellow they can be used for fabrication of luminescent color screens.

In this paper, the results of laser formation of nanostructures of titanium dioxide are presented. The obtained structures were modified by a nanoparticle of gold and silver. The spectra of titanium dioxide with gold and silver nanoparticles are shown.

Metal-carbon materials realize surface-enhanced Raman scattering. Such structures were synthesized using the laser irradiation of colloidal systems consisting of carbon and noble metal nanoparticles.

We present the experimental and theoretical results of the study of laser modification of the solid phase of thin epitaxial films of lead telluride under continuous irradiation. An ensemble of nanoparticles with bimodal distribution depending on the laser power, beam diameter, and scanning rate of the surface is formed under laboratory conditions The process of the laser heating of a thin film is simulated, and the change in the temperature field, depending on the conditions of laser exposure, is described. The experimental results are interpreted based on the defect–deformation theory of the formation of a bimodal ensemble of nanoparticles under continuous laser irradiation. The diffusion model of cluster growth in the bulk and on the surface of a thin film demonstrates the possibility of forming a bimodal size distribution of clusters.

In this work a method of the laser synthesis of colloidal nanoparticles and the formation of liquid photonic crystals are discussed. Optical properties of the systems depending on the particle concentration, its sizes and shapes were determined.

The drop deposition of colloidal nanoparticles was performed from water-based colloidal solutions. The proposed procedure is based on the agglomeration of colloidal particles in evaporation processes. The evaporation process was resulted in the formation of clustered thin films on a glass substrate. In the experiments with bimetallic Au:Ag solutions, the clustered films are grown, the formation of the clustered films with the average height of 100 nm was achieved. Optical properties of the deposited structures were investigated experimentally. It is shown that the obtained films may become transparent and their properties are defined by their morphology.

Metal-carbon materials realize surface-enhanced Raman scattering which has been synthesized by laser irradiation of colloidal systems consisting of carbon and noble metal nanoparticles. The dependence of the Raman scattering intensity of the material composition has been investigated. The possibility of detecting of the Raman spectrum of organic dye DCM and Rhodamine 6G was demonstrated.

A method of formation of bimetallic clusters on the surface of optically transparent media is proposed. Nanoparticles of noble metals were obtained by laser ablation into a liquid. Clusters were formed by means of colloidal deposition of nanoparticles. Cluster morphology after deposition was studied by means of atomic force and scanning electron microscopy. We demonstrate transformation of the transmission spectrum of obtained structures before and after laser-induced aggregation.

Titanium oxide films are photosensitive they have unusual optical properties. This article represents the possibility of the TiO objects (rolls) obtaining with predetermined optical parameters. The article also includes the comparison between numerical and physical experiments.

International audience; Continuous wave (CW) radiation from a Yb-fiber laser (central wavelength 1064 nm, power 1–200 W) was used to initiate ablation of a gold target in deionized water and to synthesize bare (unprotected) gold nanoparticles. We show that the formed nanoparticles present a single low-size-dispersed population with a mean size of the order of 10 nm, which contrasts with previously reported data on dual populations of nanoparticles formed during pulsed laser ablation in liquids. The lack of a second population of nanoparticles is explained by the absence of cavitation-related mechanism of material ablation, which typically takes place under pulsed laser action on a solid target in liquid ambience, and this supposition is confirmed by plume visualization tests. We also observe a gradual growth of mean nanoparticle size from 8–10 nm to 20–25 nm under the increase of laser power for 532 nm pumping wavelength, whereas for 1064 nm pumping wavelength the mean size 8–10 nm is independent of radiation power. The growth of the nanoparticles observed for 532 nm wavelength is attributed to the enhanced target melting and splashing followed by additional heating due to an efficient excitation of plasmons over gold nanoparticles. Bare, low-size-dispersed gold nanoparticles are of importance for a variety of applications, including biomedicine, catalysis, and photovoltaics. The use of CW radiation for nanomaterial production promises to improve the cost efficiency of this technology.

The synthesis of nanostructured metal–carbon materials by laser irradiation is an actual branch of laser physics and nanotechnology. Laser sources with different pulse duration allow to change the heating rate with realization of different transition scenarios and synthesis materials with various physical properties. We study the process of the formation of nanostructured metal–carbon clusters and complexes using laser irradiation of colloidal systems which have been consisted of carbon micro- nanoparticle and nanoparticle of noble metals. For carbon nanoparticle synthesis we use the method of laser ablation in liquid. For the realization of different regimes of laser surface modification of the target (glassycarbon and shungite) and the formation of micro- nanoparticle in a liquid the YAG:Nd laser with a pulse duration 0.5 ms up to 20 ms (pulse energy up to 50 J) was applied. We have used the CW-laser with moderate intensity in liquid (water or ethanol) for nanoparticle of noble metals synthesis. Thus, colloidal systems were obtained by using CW-laser with λ = 1.06 μm, I ~ 105–6 W/cm2, and t = 10 min. The average size of resulting particles was approximately about 10–100 nm. The nanoparticle obtaining was provided in the colloidal solution with different laser parameters. In this work we investigated the mechanism of the metal–carbon cluster formation during the process of colloidal system irradiation which has been consisted of separate carbon, silver and gold nanoparticles. This system was irradiated by nanosecond laser (100 ns) with average power up to 50 W.

In this work a method of the obtaining and controlling parameters of the silicon nanoparticles in ethanol is discussed. Also there is an experiment on the luminescence of the obtained silicon NPs.

We report the results of continuous wave laser interactions with both gold and silver targets in the presence of different liquids (deionized water, ethanol, and glycerol). Upon moderate laser irradiation at wavelength of 1.06 nm during 30 min, nanoparticle colloids are shown to be formed with surprisingly narrow size distributions and average dispersion as small as 15–20 nm. The average particle sizes range between 8 and 52 nm for gold and between 20 and 107 nm for silver. This parameter is shown to be stable and well-controlled by such laser parameters as intensity and effective irradiation time, as well as by the choice of the liquid phase. The possibilities of an efficient control over the proposed synthesis techniques are discussed, and the results of a bimetallic Au–Ag structure deposition from the obtained colloids are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. The changes in the optical properties of the obtained thin films are found to depend on their morphology, in particular, on the particle size, and distance between them.

Nanosecond and femtosecond laser impulses applied to the stable aqueous dispersion of shungite carbon nanoparticles brought to increase in the average size of clusters and to drastic changes in structure of shungite carbon that were obtained from its Raman spectra decomposition.

The laser synthesis technique for producing nanoparticles/nanoclusters of different topology for semiconductor samples (PbTe) is presented by two laser ablation methods: direct laser modification of thin films and laser evaporation of substance from the target in liquid (ethanol) to produce a colloidal system, and the subsequent laser deposition of the particles from colloid on solid substrate [under continuous wave (cw)-laser, λ = 1.06 μm, laser intensity—up to 106 W/cm2]. Electro-physical properties of the induced structures have been controlled by various induced topology. It is obtained that electroresistance can dramatically decrease due to spontaneous selected multichannel/parallel electron transportation trajectories in the inhomogeneous cluster system. Two conditions are principal for that: the characteristic cluster size a

In this work a method for the laser formation of C-Au-Ag clusters and complexes on the surface of an optically transparent media is discussed.

Synthesis of transparent conductive coatings is a promising direction of modern nanotechnological research. Thin nanostructured noble-metallic films demonstrate nonlinear optical effects in visible spectral range because of their plasmonic properties [1]. In addition, optical characteristics of these thin films strongly depend on the period of the formed surface structures [2]. If the distance between deposited particles almost equals their sizes, the optical properties of the randomly deposited structures may considerably differ from these for periodical structures [3]. In this work, we have studied the degree of the morphology influence (particle diameter in the colloid, the distance between the deposited particles, the number of layers etc.) on the optical and electrical properties of the deposited thin film of bimetallic gold and silver clusters. In this work we used CW-laser with moderate intensity in liquid (water or ethanol) for synthesis nanoparticles of noble metals. For the formation of quasi-periodically arranged clusters, particle deposition from the colloidal systems is used. The optical properties of the deposited bimetallic films are shown to change as a function of composition and geometry in agreement with the modeling of the optical properties. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Synthesis of nanotructured metal-carbon materials by laser irradiation is an actual branch of laser physics and nanotechnology. Laser sources with different pulse duration allow changing the heating rate with realization of different transition scenarios and synthesis materials with various physical properties. We study the process of the formation of nanostructured metal-clusters and complexes using laser irradiation of colloidal systems which were consisted of carbon micro- nanoparticles and nanoparticles of noble metals. For carbon nanoparticles synthesis we use the method of laser ablation in liquid. For the realization of different regimes of laser surface modification of the target (glassycarbon and shungite) and the formation of micro- nanoparticles in a liquid the YAG:Nd laser with a pulse duration from 0.5 ms up to 20 ms (pulse energy up to 50J) was applied. We have used the CW-laser with moderate intensity in liquid (water or ethanol) for nanoparticle of noble metals synthesis. Thus, colloidal systems were obtained by using CW-laser with λ = 1.06 μm, I ~ 10 5-6 W/cm 2 , and t = 10 min. The average size of resulting particles was approximately about 10 to 100 nm. The nanoparticle obtaining was provided in the colloidal solution with different laser parameters. In this work we have investigated the mechanism of the metal-carbon cluster formation during the process of irradiation of colloidal system which were consisted of separate carbon, silver and gold nanoparticles. This system was irradiated by nanosecond laser (100 ns) with average power up to 50W.

International audience; Gold nanoparticles (Au NPs) attract particular attention because of their unique size-dependent chemical, physicochemical and optical properties and, hence, their potential applications in catalysis, nanoelectronics, photovoltaics and medicine. In particular, laser-produced colloidal nanoparticles are not only biocompatible, but also reveal unique chemical properties. Different laser systems can be used for synthesis of these colloids, varying from continuous wave (CW) to ultra-short femtosecond lasers. The choice of an optimum laser system is still a challenge in application development. To bring more light at this issue, we investigate an influence of laser parameters on nanoparticle formation from a gold target immersed in deionized water. First, an optical diagnostics of laser-induced hydrodynamic processes taking place near the gold surface is performed. Then, gold nanoparticle colloids with average particle sizes smaller than 10 nm and a very narrow dispersion are shown to be formed by CW laser ablation. The obtained results are compared with the ones obtained by using the second harmonics and with previous results obtained by using femtosecond laser systems. © (2016) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

We study the formation and deposition of clusters of nanoparticles from colloidal systems onto a support surface as a result of local pulse laser impact. The processes of abnormal diffusion influencing the formation of relief due to changes in the diffusion coefficient near surface irregularities are analyzed. Numerical simulation is performed for the mechanism of deposition of particles from the colloidal system as a result of local laser impact.

The paper demonstrates that the laser ablation approach can be used for synthesis (with average nanoparticle size control) of silicon nanoparticles supporting strong resonant optical responses in the visible spectral range. Porous and monolithic crystalline silicon targets are considered. The generated colloidal solutions have been used for the formation of one-layered covering composed of silicon nanoparticles. The obtained results may be used for the realization of many functional metasurfaces consisting of randomly distributed resonant nanoparticles.

Metal–carbyne materials, synthesized by laser irradiation of colloidal systems consisting of carbon and noble metal nanoparticles, are promising objects to realize surface-enhanced Raman scattering. The dependence of the Raman scattering intensity of the material composition has been investigated. The possibility of detecting of the organic dye Rhodamine 6G Raman spectrum was demonstrated.

We report for the first time the formation of a nanoparticle ensemble on a binary semiconductor (PbTe) film under cw laser irradiation. It is shown that defect — deformation theory of the formation of nanoparticle ensembles in the solid state under cw laser irradiation adequately describes experimental data. In particular, it predicts a bimodal nanoparticle size distribution function that agrees well with the experimental distribution function.

In this work, a method for the formation of Au, Ag and bimetallic Au-Ag clusters on the surface of an optically transparent media is discussed. Nanoparticles of noble metals were obtained by laser ablation targets of gold and silver in liquid. Laser ablation of solid targets in the liquid medium widly used method for fabrication nanostructures with various compositions such as metals, alloys, oxides, carbides, hydroxides, etc. At the same time a great advantage of the method is the possibility to re-irradiate the suspended nanomaterials that can be applied to further modify their size, shape, and composition. In the past two decades, with the rise of nanoscience, laser ablation has been broadly applied and developed for the synthesis of noble metal nanostructures such as gold (Au), silver (Ag), platinum (Pt) and palladium (Pd) or their alloys. Bimetallic structures of these metals have improved physical and chemical stability and selectivity compared with isometric structures. The bimetallic complex is related to change the optical properties, in particular transmission and absorption, depending on the nanoparticles (NPs) size and composition. Separate direction of controlling the optical properties of such nanostructures formation of clusters with variable morphology. Promising method of obtaining bimetallic clusters is the laser formation of colloidal alloys. In this work we used two different schemes of laser ablation in liquid (water, ethanol, etc.)

Metal–carbon materials exhibiting surface-enhanced Raman scattering have been synthesized by laser irradiation of colloidal systems consisting of carbon and noble metal nanoparticles. The dependence of the Raman scattering intensity on the material composition has been investigated. The possibility of detecting of the Raman spectrum of organic due DCM and rhodamine 6G is demonstrated.

In this work the results of a bimetallic Au-Ag structure deposition from the colloidal system by nanosecond laser radiation are presented. The formation of the extended arrays of gold and silver nanoparticles with controlled morphology is examined. We report the results of formation bimetallic islands films with various electrical and optical properties. The changes in the optical properties of the obtained thin films are found to depend on their morphology.

The main goal of our work is the laser fabrication of nanostructured materials including the nano- and microclusters for control of electrical, optical and other properties of obtained structures. First, we took an opportunity to select nanoparticles in various sizes and weights and also in topology distribution for some materials (carbon, Ni, PbTe, etc). Second, for a deposited extended array of nanoparticles we used a method of laser-induced nanoparticle fabrication in colloid and deposition metal (and/or oxide) nanoparticles from colloidal systems (LDPCS) to obtain the multilayered nanostructures with controlled topology, including the fractal cluster structures (for Ni, Pb Te et al). Electrophysical properties are analyzed for such nanocluster systems as well. A brief analogy of the obtained nanocluster structures with a quantum correlated state evidence is carried out.

We present the results of laser production of semiconductor nanoparticles under continuous laser action in the near-infrared range (up to 106?W?cm?2) on PbTe samples in air and liquid. We also present a method for forming nanoparticles on the surface of thin PbTe films and consider drop deposition for setting PbTe quantum dots on a substrate. Using a simulation model we describe the features of forming a deposited layer in the process of drop?evaporation.