Picosecond and Nanosecond Nd:YAG laser systems with a fundamental wavelength of 1064 nm are utilizedfor green synthesis of bimetallic nanocomposites based on metal combinations of Pt/Ti, Pd/Ti, Pt/Zn and Pd/Zn. The laser assisted method is based on pulsed laser ablation of metal targets, which are immersed consecutively in bidistilled water to obtain water colloids of the corresponding bimetallic nanostructures. Comparative study of the structural and optical properties of the nanocomposites is conducted by means of transmission electron microscopy in its corresponding main modes and by optical spectrometer measurements, respectively. Suspensions of water colloids of the nanocomposites and methylene blue dye prepared in 1 : 2.5 ratio, respectively, are exposed under sunlight irradiation for 3 h. Photocatalytic activity of the nanocomposites against methylene blue (MB) dye is tested by measuring the optical absorbance of the suspensions before and after the sunlight irradiation.

The present work reports the fabrication of porous composite ZnO/noble metal (Ag, Au) nanostructures using ps-pulsed laser deposition at atmospheric pressure. The PLD grown samples are ns-laser annealed, which led to a surface modification and formation of nanoparticles and NP’s aggregates. The effect of laser annealing procedure on the morphology, structure and optical properties of composite nanostructures is studied. The experimental results indicate that the laser annealing changes the plasmon resonance absorption mostly in the silver-doped samples. The laser modification plays a key role in tuning the PL performance for all samples by different mechanisms. Along with the increase in UV emission, there is a corresponding decrease in the broadband defect emission with the laser modification of composite nanostructures. The plasmon resonance absorption contributes to the enhancement of photoluminescence band-edge UV emission of the silver doped samples, while the PL performance of nanostructured ZnO/Au samples is attributed to the surface-plasmon-mediated sequential transfer of defect energy from ZnO to Au and electron transfer from excited Au to ZnO.

In this work formation of conductive lines on the surface of AlN ceramic induced by laser radiation is presented. The transformation to conductive state is done be ablation of the ceramic surface using nanosecond Nd:YAG laser. The dependences of the processing conditions as applied laser fluence and the pulse overlapping on the resistance value are obtained for different surface modifications including straight lines, L, and + shapes. The formation of conductive structures is also studied for application of laser irradiation at the second (532 nm), third (355 nm) and fourth (266 nm) harmonics of the laser system. It is found that the resistance strongly depends on the processing conditions, as at appropriate choice it can be varied in a range of order of magnitude. Processing parameters windows are defined where the structure resistance has a minimal value. The performed analyses based on TEM, SEM, EDX, and Raman spectroscopy indicate that formation of aluminium layer, its oxidation and morphology define the processed areas conductivity. The role of oxidation is also confirmed by analyses of structures fabricated in vacuum, where significant reduction of the resistance is observed. It is found however, that a decrease of the ambient air pressure to 10 Torr is sufficient to obtain structures resistance of the same order as for processing in vacuum. Calculated data about the thickness of the conductive layer is also presented. The obtained results could be used in the design of microelectronic components, resistive elements, and novel optical materials.

Ag/ZnO nanostructures were synthesized using pulsed laser deposition (PLD) in open air (at atmospheric pressure). The deposition was carried out by a Nd:YAG laser, with the Ag layer composed of nanoparticles grown on SiO2 (001) substrates by the laser wavelength of 355 nm; this layer was covered by ZnO deposited by using the laser wavelength of 1064 nm. The samples were laser annealed, which led to a modification of the nanoparticles. The nanocomposites produced were characterized by TEM, UV-Vis and PL spectroscopy. The annealing procedures influence the optical properties of the Ag/ZnO nanocomposites. The laser annealing under certain parameters changes the emission behavior of the Ag/ZnO nanocomposite heterostructures. By employing localized surface plasmon resonance (LSPR), the near band edge (NBE) emission intensity of the ZnO films composed of nanoparticles was varied. An enhancement of the UV emission located at about 383 nm, commonly attributed to an excitonic transition, was registered after laser annealing with one pulse at the wavelength of 355 nm. The results obtained demonstrate that the annealing of Ag/ZnO composite nanostructures plays a key role in tuning the PL performance of a semiconductor material where an LSPR occurs.

In this work, the surface modifications are studied of aluminium nitride (AlN) and silicon nitride (Si3N4) ceramics irradiated by nanosecond laser pulses. The laser processing is performed by a Nd:YAG laser system at four wavelengths - 266 nm, 355 nm, 532 nm, and 1064 nm. It is found that the average ablation rate per pulse is in the order of few hundreds of nanometers, as the laser treatment leads to the appearance of a variety of micro- and nanostructures on the surface of the material. In the case of AlN, a conductive layer is formed on the surface whose resistance can be modified by varying the processing conditions. Using a model based on the heat-conduction equation, the temperature evolution, ablation depth and temporal dynamics of the ablation process are followed.

The optical characteristics of Ag/ZnO composite nanostructures have long been of particular interest and, thus, the subject of broad experimental and theoretical studies. This work is focused on the synthesis and properties of Ag/ZnO nanocomposites and demonstrates the possibility of their application as active substrates for surface-enhanced Raman spectroscopy (SERS) in detection of pesticides. The samples were synthesized by pulsed laser deposition (PLD) of ZnO thin films, followed by Ag + -ion implantation in the ZnO matrix and by laser annealing of the heterostructures produced. The morphology and properties of the samples were studied with respect to the processing parameters. The optical absorption studies revealed the existence of tunable surface plasmon resonance of silver nanoparticles in the ZnO matrix. Theoretical calculations of the optical properties, as extinction, absorption and scattering efficiencies, were performed based on a generalized multi-particle Mie (GMM) approach. The simulated system assumed in this comparative study consists of a surface-embedded ensemble of silver nanoparticles in a ZnO surrounding media and in air. The simulated structures were reproduced from the corresponding SEM images after laser annealing at 355 nm and 532 nm.

The present study is focused on the development of advanced technology for creation of plasmonic composite nanostructures for Surface Enhanced Raman Spectroscopy (SERS) detection of ammonium nitrate. The investigation of the interaction of nanostructured composite objects with electromagnetic field, the description of their optical properties as well as determination of mechanisms and conditions for their effective modification brings the information for potential application as SERS substrates. The ZnO thin films are deposited by pulsed lased deposition (PLD) in an oxygen environment at high substrate temperature. The laser grown ZnO films are modified by Ag-ion implantation. The produced nanocomposites are subsequently laser annealed at different laser wavelengths. The influence of the ion implantation doses and the laser annealing parameters on the SERS activity of produced nanostructures is investigated. The observation of morphology of the samples demonstrates the influence of the laser annealing wavelength on the size distribution of embedded silver nanoparticles on the ZnO matrix. The plasmonic behaviour of embedded metal nanoparticles is determined by studying the optical properties of the fabricated structures. The proposed combined method for synthesis has potential application in fabrication of reliable substrates for Raman spectroscopy analysis with high sensitivity. The design of appropriate structures by laser and ion implantation methods can increase the efficiency of the high resolution analyses.

In this work, results on a new laser-induced mechanism of microstructures formation on the surface of borosilicate glass are presented. The samples are fabricated by melt quenching method and consist of 50% SiO2, 20% Al2O3, 20% B2O3, 5% CaO, 2% Li2O, 3% MgO (in wt.%). Irradiation at 266 nm delivered by Nd:YAG nanosecond system is used to modify the glass surface. It is found that this processing may result in the formation of voids in the irradiated area that have submicron mean diameter. The effect is observed at fluences below the ablation threshold. Different laser fluences and pulse number are applied to estimate their role on the induced surface morphology. It is observed that voids are also observed in the remaining material after ablation of the irradiated zone at high fluences. In this regime, glass structure modifications can also be observed under the glass surface at depths that may reach 100 µm. Based on measurements by differential thermal analysis equipped by mass spectrometer is concluded that the void formation is related to emission of gas phase from the glass induced by the laser heating.

Ag/ZnO composite nanostructures are produced by combined laser and ion implantation techniques. The ZnO layers are grown on SiO 2 (001) and Al 2 O 3 (r-cut) substrates by pulsed laser deposition (PLD) in vacuum and in oxygen ambient using a third-harmonic Nd:YAG laser. The ion implantation allows the introduction of Ag nanoparticles (NPs) in the surface of the ZnO matrix. These NPs are incorporated into the ZnO matrices to fabricate metal-semiconductor nanocomposites with the aim of manipulating their functionalities, exploiting the characteristics of both the matrix and the metal NPs. The composite samples are modified by laser annealing at 355 nm and 532 nm. The changes are investigated in the plasmon resonance absorption of the nanostructures before and after the annealing. The influence is explored of the different substrates used and the deposition conditions of ZnO growth on the properties of Ag/ZnO. The nanostructures obtained are efficient as SERS substrates for detection of ammonium nitrate under laser excitation at 633 nm. The SERS enhancement is attributed to the synergistic interactions between the plasmonic coupling among the surface embedded AgNPs and the enhanced charge transfer properties of the ZnO.

We present a microstructural study of nanocomposite samples based on iron oxide and a noble or a transition metal. The samples were produced by laser ablation in air at atmospheric pressure in the presence of a magnetic field. This technology allows production of oriented nanowires composed by nanoparticles. We applied a simultaneous laser ablation of two targets in an external magnetic field. The targets used for the ablation were a magnetic material (iron) and a noble or a transition metal (silver, gold or cobalt). The presence of a magnetic field during the deposition results in arranging the nanoparticles formed in the plasma plume into micrometric nanowires on the substrate. The structural analyses confirms that the samples are composed by iron oxide and a noble or a transition metal.

The paper presents results on femtosecond laser irradiation-induced modification of the optical properties of a composite material – gold nanoparticles embedded into a borosilicate glass host. The process is initiated by laser pulses delivered by a Ti:sapphire laser system with pulse duration of 35 fs. The glass samples are prepared by melt quenching with gold added as hydrogen tetrachloroaurate (III) hydrate to the initial composition. Post-fabrication annealing leads to a homogeneous formation of nanoparticles in the glass; varying the annealing parameters results in producing nanoparticles with different sizes and shapes. The laser irradiation of the samples induces significant modification of the optical spectra of the glass through changes of the nanoparticles characteristics. The effects are studied of the laser fluence, laser wavelength and laser pulses number. The heat diffusion equation is applied to estimate the temperature evolution and explain the modifications observed. The results demonstrate this technique’s efficiency in modifying the nanoparticles properties with a high 3D spatial resolution, which can be useful in fabrication of integrated optical systems.

The present work concerns the fabrication and the investigation of Ag nanoparticles, surface embedded in the pulsed laser deposition (PLD) grown ZnO thin films. The third-harmonic Nd:YAG laser is used for PLD of ZnO thin films. The ion implantation technique for Ag doping in ZnO matrix is used. The morphology, texture and composition of the samples are investigated. The Ag distribution in the implanted near-surface region is investigated as a function of the processing conditions. The influence of the substrate temperature and ambient oxygen pressure during the PLD growth of ZnO films is studied. The applied processing parameters during the deposition of ZnO thin films lead to different microstructure of ZnO host matrix and have a significant impact on the properties of subsequently produced Ag/ZnO nanocomposites. The changes of optical surface plasmon resonance (SPR) band of synthesized Ag nanoparticles for different morphologies are analyzed for implanted samples. The composite nanostructures are found to exhibit SPR absorption properties of metal nanoparticles after the ion implantation, especially pronounced for the samples with laser grown ZnO matrix at high substrate temperatures. This study demonstrates how the different crystal structure of the ZnO supporting material, influences the Ag implantation process and, respectively, the properties of the produced Ag/ZnO nanocomposites.

Noble metal nanoparticle composed glasses attract significant attention due to the unique optical properties that they express in the near UV and visible spectral range. These are related to the high values of the extinction cross section and nonlinear optical characteristics. In this work we study the ability of laser irradiation to induce modification of the optical properties of borosilicate glasses that contain gold nanoparticles. The process is investigated by application of laser pulses of nanosecond Nd:YAG system on glasses that consist of nanoparticles with different size and shape. The results show that at certain conditions the glass optical properties can be modified as a change of the nanoparticles plasmon resonance wavelength is observed. The influence of the laser fluence and pulse number on this effect is studied. Two fluence regimes are defined: (i) at low fluences, close to the optical properties modification threshold the increase of the laser fluence results in a blue shift of the resonance wavelength; (ii) further increase of the laser fluences induces a red shift. Similar behavior is observed by changing the number of the applied pulses. Here after application of several thousand laser pulses additional, third regime of blue shift is realized. Theoretical models based on multiparticle Mie scattering theory and heat conduction equation are applied to explain the observed modifications. On their basis and performed analyses can be concluded that the induced optical properties variations are related to modification of the nanoparticles size and shape by melting, fragmentation and coalescence. The obtained results indicate an ability of nanoparticle size and shape modifications with a high spatial resolution in 3D and can be used for fabrication of integrated optical systems.

This work represents results on the response of noble metal-doped borosilicate glass to laser radiation with femto- and nanosecond pulse duration. The material under study is obtained by conventional melt quenching method as samples with noble metal concentration varied up to 10 wt% are fabricated. Optical and morphology changes of the glass samples induced by application of laser pulses with a wide range of parameters are studied. Below the permanent modification threshold, defects associated with formation of color centers in the material are observed and their properties as a function of the processing conditions are discussed. It is found that at certain conditions laser irradiation may induce direct formation of noble metal nanoparticles in the glass. When permanent morphology modifications are induced, different micro-and nanostructures are observed depending on the laser parameters. The morphology of the ablated area is studied as function of the laser fluence and number of the applied pulses. It is found that the presence of noble metal in the glass at concentrations up to 10 wt% (the maximal used) does not influence the ablation rate at both femto- and nanosecond ablation. The formation of defects and the composition of the material in the vicinity of the ablated zone are also discussed.

The process of laser radiation-induced formation and decomposition of Ag nanoparticles in glass is studied. Borosilicate glass samples are fabricated by melt quenching method. Silver nitrate is added in the fabrication stage in amount to form final glass samples with compositions of 1, 1.5, 5, and 10 wt% Ag. The fabricated samples are irradiated by laser pulses delivered by Nd:YAG nanosecond laser system at wavelength of 266 nm. It is found that at certain conditions laser radiation can induce coloration of the irradiated zone which is related to formation of silver nanoparticles. Detailed analyses are performed to characterize the formed nanoparticles. The application of a subsequent laser treatment of the glass samples with already formed nanoparticles can result in transparency recovery. The effect is demonstrated at wavelength of 355 nm of the Nd:YAG laser system. The observed formation and decomposition of nanoparticles are discussed on the basis of the calculated laser-induced heating dynamics and molecular dynamics simulation model for the silver atom motion. Diffusion growth and redox reactions are found to be responsible for the observed effects.

This paper describes the luminescence properties of small silver clusters formed by laser treatment of silverdoped borosilicate glass. Using irradiation by a Nd:YAG nanosecond laser system operating at the fourth harmonic wavelength (266 rim), areas are formed in the glass samples that emit bright luminescence peaking at about 600 nm when excited by UV light in the spectral range 300-390 nm. The influence is presented and discussed of the glass composition and the laser processing parameters on the emission characteristics. It is further shown that the luminescent properties are affected by the fluence of the excitation source, namely, a complete quenching of the emission is achieved above a certain value. The luminescence of the irradiated areas is explained by the formation of Ag clusters due to irradiation-induced reduction of Ag ions and increased atom mobility resulting from the local heating. The limited stability of the luminescent areas upon UV radiation can be related to heat-induced cluster decomposition and re-oxidation. The results obtained provide a new insight in the optical properties of noble-metal nanostructures and could form the basis of fabrication of complex optical systems and luminescent component used in the study of, e.g., biological systems.

Our Orthonormal Polynomial Expansion Method (OPEM) in one-dimensional version is applied to describe the original different silver nanoparticles spectroscopic data. We construct orthogonal (orthonormal) polynomials for presenting the curves. The corridors defined by errors of given data by the help of the weights construct the optimal behavior of sought for curve. We have received from experiments some curves in thousands points for analysis, but two of them are important-with ten and five laser pulses. In this way the paper is a continuation and a generalization of the investigation in the previous paper. We have chosen the subintervals in two curves. The most important subintervals of spectra data are investigated, where the minimum (Surface Plasmon Resonance Absorption) is looking for. This study describes the Ag nanoparticles produced by laser approach in a ZnO medium forming a AgNPs/ZnO nanocomposite heterostructure.

A novel and effective approach is suggested for fabrication of composite Ag/ZnO nanostructures for surface-enhanced Raman scattering (SERS) by combining laser and ion implantation techniques. The study explores the relation between the nanoscopic features of the prepared Ag/ZnO nanocomposites and their effectiveness as SERS active substrates. The ZnO thin films are grown by pulsed laser deposition (PLD). Ag+-ion implantation is used for surface synthesis of Ag nanoparticles (NPs) in the ZnO matrix. The implanted samples are annealed by a Nd:YAG laser at various parameters. The surface morphology, composition and optical properties of the nanocomposites are studied before and after the ion and laser modifications. The possibility to apply these structures to ammonium nitrate detection is investigated by identifying the most suitable conditions for laser annealing of the implanted Ag/ZnO structures in view of producing the strongest SERS signal. A comparative Raman study is performed at two laser excitation wavelengths. New results are obtained for different ammonium nitrate (AN) concentrations. The strongest Raman signal of ammonium nitrate is detected for the Ag/ZnO substrate annealed at 532 nm and characterized by a high surface roughness and a wide nanoparticles' size distribution, where a low surface electron density of silver was obtained.

In this work results on laser assisted formation of silver nanoparticles in glass are presented. The sample material used in the experiments is Ag doped borosilicate glass fabricated by conventional melt quenching method. The glass samples are irradiated by nanosecond laser pulses at wavelength of 266 nm with a wide range of fluences and number of applied pulses. It is found that the laser radiation can lead to specific yellow coloration of the irradiated areas. The performed analyses show formation of silver nanoparticles in these zones. The optical properties of the irradiated areas are found to depend on the laser processing parameters and the silver concentration. The mechanism of nanoparticle formation is also discussed. The presented method can be used for formation of nanoparticles inside transparent materials and can be used for fabrication of novel materials with application in photonics.

The present study focuses on the synthesis of noble metal (Au, Ag) nanoparticles and their incorporation and manipulation in thin film oxide matrix. The structural and functional properties of the nanoparticles embedded in a host matrix of fused SiO2 films are covered by this research. The effect of post-deposition laser or thermal annealing procedures on the behaviour of laser fabricated composite nanostructures is investigated. The coloration of samples is determined by the nano-sized metal particles in a dielectric matrix, due to a surface plasmon resonance effect of the conductive electrons and respective selective absorption. The laser deposition and annealing are performed by a nanosecond Nd: YAG laser at fourth and third harmonics, respectively. The estimation of the temperature and the heating and cooling rates due to the laser annealing is performed. The influence of the nanosecond UV-laser annealing on the optical spectra and plasmon resonance properties of the samples is investigated. The experimental results indicate that the annealing induces plasmon resonance absorption in Ag/SiO2 nanocomposite and a red-shift of the existing resonance absorption of Au/SiO2. The tuning of the optical properties of the samples was interpreted as a function of their morphology and structure, formed at certain parameters in the processing stages of laser deposition and annealing.