In this research, wettability control by area fraction of laser ablated surface of copper is presented. The functional surfaces with full wettability control from highly hydrophilic to super-hydrophobic were created on copper by nanosecond (ns) and picosecond (ps) laser irradiation. The area fraction and color change were evaluated by digital image processing of microscopic images of the laser-ablated copper surface. The control of the wetting angle from almost 0 degrees to 132 degrees was achieved for both ps and ns pulses by controlling the area fraction of the laser-ablated surface. Cassie, Cassie-Baxter, and Wenzel models were adopted to explain the experimental results. For the first time, the wettability and color of copper were controlled by controlling the area fraction of the laser-ablated surface. It is expected that the current results make an impact on the heat exchanger technology of water heat sinks, cooling units, atmospheric water generators, and fog harvesting and impact numerous applications from power plants to solar thermal water systems devices where highly-hydrophilic to super hydrophobic copper can be applied.

Nanocellulose was made in the form of water gel using chemical and ultrasound treatments of the Miscanthus x giganteus plant. Properties both of nanogel and of its thin solid films deposited on glass, silicon and microcrystalline cellulose substrates were studied. Nondestructive methods (XRD, viscosymetry, scanning electron and optical microscopy, reflection and luminescence spectroscopy) were used to characterize studied materials. The results obtained allowed estimation of nanofibrils sizes both in water solutions and in the solid states. It was found that the aspect ratio for the nanofibrils (p = l/d, where l is the length and d - diameter) in the nanogel state decreases from 130 to 20, when temperature increases from 15 to 75 & DEG;C. The value of p for nanofibrils in solid films is in the range of 3-30. It was assumed that mentioned data are the result of aggregation of the nanofibrils in the solid state and under water nanocellulose gel cooling. The data about optical properties of the nanocellulose under study showed that optical reflection and photoluminescence methods are suitable, in principle, for characterization of nanocellulose made from Miscanthus x giganteus in the form of nanogel, too.

A dependence of the CT exciton lifetime on the cobalt phthalocyanine molecular stacking is observed. We ascribe such behavior to the different π-conjugation along the stacking axis, favoring the CT exciton delocalization in the herringbone geometry.

Co-doped with Ca2+ and Er3+ ions LaVO4:Eu crystalline nanoparticles are synthesized and investigated with a goal to clarify the mechanisms of Ca2+ and Er3+ impurities effects on Eu3+ ions luminescence and to find compositions with enhanced luminescence intensity. The XRD analysis reveals dependence of crystal structure on dopants concentration: monoclinic crystal phase is observed for low dopant concentrations and content of tetragonal crystal phase increases with dopant concentrations increase. The SEM investigation reveals formation of nanoparticles with two types of shapes. Photoluminescence spectra consist of lines caused by f-f transitions in the Er3+ and Eu3+ ions. It has been shown that dependence of the Eu3+ ions luminescence intensity on the Er3+ and Ca2+ concentrations is caused by cumulative effects of dopants on crystal lattice structure, on defects in the first coordination sphere of the Eu3+ ions and on efficiency of excitation energy transfer. The maximal luminescence intensity is found for the La0.8Er0.05Eu0.05Ca0.1VO4 composition. The corresponded intensity is as much as 19 +/- 2 and 8 +/- 2 times higher than luminescence intensity of the La0.95Eu0.05VO4 and La0.9Eu0.05Ca0.05VO4 compounds, respectively. Conclusion is made that Er3+ and Ca2+ ions co-doping is a promising way to increase luminescence efficiency of the Eu3+ ions in the LaVO4 nanocrystals.

A comprehensive report is provided here on a single‐step approach to the selective surface processing and functionalization of glass components with laser pulses. In particular, it is shown that biomimetic, self‐organized, deep‐subwave‐length, quasi‐periodic nanopillar structures can be realized using ultrashort laser light. These structures have an enormous effect on the properties of the glass, including optical and wetting. Remarkable antireflection and enhanced transmission, tunable glare as well as a strong antifogging effect of the laser processed glass are shown. Several use cases are discussed for selective glass surface functionalization, including optical fiber tips and curved optical lenses.

The sufficient control of the carrier density of a single layer WS2 (1L-WS2) has been realized by the pulsed laser irradiation doping technique. Chlorine atoms are incorporated on the surface of the atomically thin lattice in a precursor gas atmosphere. In this work, we demonstrate spin-valley polarization tunability by more than 40% in 1L-WS2 on hBN via photochlorination. Polarization photoluminescence spectroscopy was performed in the temperature range from 4K to 300K. The decrease in circular polarization after the photochlorination treatment is attributed to the significant reduction of the active defect sites in 1L-WS2 and, consequently, to the increase in the non-radiative exciton lifetime. Ultrafast time-resolved transient absorption spectroscopy measurements support our findings. The above results indicate a useful approach of controlling the density of the active defect sites and the valley polarized light emission in doped monolayer crystal lattices.

The EuVO4 nanoparticles doped with Ca2+ impurities were synthesized by citrate-nitrate sol-gel method and investigated. Diffuse reflection spectra of the EuVO4:Ca samples contain two additional bands around 400 and 470 nm those were not observed for the undoped EuVO4. These bands were ascribed to Ca-induced defects in the vanadate crystal lattice. Origin of these defects is studied taking into account results of high resolution XRD measurements. The additive XRD peaks were found for the Eu0.8Ca0.2VO4, sample. These peaks were identified as traces of the Ca2V2O7 second crystal phase in the synthesized nanoparticles. The maximal concentrations of the Ca2+ heterovalent impurity permits to keep single phase EuVO4:Ca sol-gel nanoparticles were estimated.

Thin films containing luminescent active vanadate nanoparticles were applied by spin-coating, solution evaporation and pulsed laser deposition methods on glass substrates. The films are formed by pure vanadate layers as well as by silicon gel layers used as matrices and incorporated with vanadate nanocrystallites. Morphology of the films was studied using optical, atomic force and scanning electron microscopy. It was shown that films obtained from the same compositions but under different procedures have different morphology. Optical properties of the films were studied using absorption, reflection and luminescence spectroscopy in comparison with properties of the initial vanadate nanoparticles. Influence of procedure methods and growth conditions on spectral characteristics of the films was discussed. Advantages and disadvantages of the noted methods of luminescent films growing from vanadate nanoparticles were studied and discussed.

Results on the manipulation of the wetting properties of stainless steel alloy surface by ultrashort pulse laser texturing are presented. The wide range of water droplet contact angles from highly-hydrophilic to super-hydrophobic was achieved by generation of laser-induced periodic surface structures (LIPSS) and nanospikes. In particular, the wetting state was controlled by accumulated laser fluence, which determines the carbon/oxygen content and nano-texture type of the surface after laser treatment. A super-hydrophobic water-repelling surface was generated. The simple, single-step laser processing technology was demonstrated as a promising tool for the large-scale industrial production of self-cleaning stainless steel.

The exciting properties of micro- and nano-patterned surfaces found in natural species hide a virtually endless potential of technological ideas, opening new opportunities for innovation and exploitation in materials science and engineering. Due to the diversity of biomimetic surface functionalities, inspirations from natural surfaces are interesting for a broad range of applications in engineering, including phenomena of adhesion, friction, wear, lubrication, wetting phenomena, self-cleaning, antifouling, antibacterial phenomena, thermoregulation and optics. Lasers are increasingly proving to be promising tools for the precise and controlled structuring of materials at micro- and nano-scales. When ultrashort-pulsed lasers are used, the optimal interplay between laser and material parameters enables structuring down to the nanometer scale. Besides this, a unique aspect of laser processing technology is the possibility for material modifications at multiple (hierarchical) length scales, leading to the complex biomimetic micro- and nano-scale patterns, while adding a new dimension to structure optimization. This article reviews the current state of the art of laser processing methodologies, which are being used for the fabrication of bioinspired artificial surfaces to realize extraordinary wetting, optical, mechanical, and biological-active properties for numerous applications. The innovative aspect of laser functionalized biomimetic surfaces for a wide variety of current and future applications is particularly demonstrated and discussed. The article concludes with illustrating the wealth of arising possibilities and the number of new laser micro/nano fabrication approaches for obtaining complex high-resolution features, which prescribe a future where control of structures and subsequent functionalities are beyond our current imagination.

Thin films from the LaVO4:Eu, Ca nanoparticles were successfully grown by pulsed laser deposition method on glass and silicon substrates for the first time. Morphology and thickness of the films depend on the type of substrate and number of pulses. The films are of 27–220 nm thickness and formed by very small particles (up to 20 nm) and also can contain single nanoparticles with dimensions of 40–60 nm and sometimes agglomerates of nanoparticles. Spectral properties of the samples have been investigated and discussed. The vanadate films deposited on the silicon substrates lead to appearance of antireflection properties in the visible range. Luminescence spectra of the investigated films consist of narrow lines caused by f–f transitions in the Eu3+ ions. For the samples on glass substrates the wide bands of glass emission also contributed to the spectra. The optimal experimental conditions which allowed to obtain films with promising applications as luminescent converters are considered.

The Eu and Ca-doped LaVO4 luminescent vanadate nanoparticles synthesized by sol-gel method have been successfully applied on silicon and solar cell substrates by pulsed laser deposition method for the first time. Morphology and structure of the obtained films were investigated. The films are formed by very small particles (up to 20 nm) and also can contain some agglomerates of nanoparticles. Optical properties of the samples have been studied and discussed. The vanadate films have caused improvement of antireflection properties of the used substrates. Luminescence spectra of the deposited films consist of spectral lines corresponded to f-f transitions in the Eu3+ ions. Spectra of the samples on solar cell substrates contain also very weak wide bands caused by emission of substrate. The optimal conditions of deposition of nanoparticles for obtaining of films promising for applications as luminescent spectral converters for improvement of efficiency of silicon solar cells are discussed.

Nature has provided a plethora of functional surfaces exhibiting unique, complex hierarchical morphologies with dimensions of features ranging from the macroscale to the nanoscale. Such morphologies are behind the superior properties exhibited by the natural surfaces, including extreme wetting [1], antireflection [2], floatation, adhesion, friction and mechanical strength [3]. In principle, femtosecond laser induced surface structuring has been employed to produce numerous biomimetic structures for a range of applications, including microfluidics, tribology, tissue engineering and advanced optics.

The La1−xEuxVO4 (0 ≤ x, y ≤ 0.3) and La1−x−yEuyCaxVO4 (0 ≤ x, y ≤ 0.2) nanoparticles were synthesized by various methods and investigated. Phase composition of the sample depends on the x, y values. The La1-xEuxVO4 can be crystallized in monoclinic structure up to x = 0.1 or x = 0.05 depending on the method of synthesis. The La0.9Eu0.05Ca0.05VO4 sample was also attributed to the monoclinic structure. Increasing concentration of europium and calcium ions in La1−x−yEuyCaxVO4 solid solutions leads to the change of the crystal structure and subsequently stabilization of the tetragonal phase takes place. The obtained samples were characterized by XRD analysis, SEM microscopy, and IR spectroscopy. Luminescence properties of the synthesized powders were studied. Emission of all the La1−xEuxVO4 and La1−x−yEuyCaxVO4 samples consists of narrow spectral lines in the 550 – 730 nm spectral range. The lines are caused by the 5D0 → 7FJ electron transitions in the Eu3+ ions. The Ca2+ ions incorporation increases intensity of the Eu3+ ions luminescence. The structure of the spectra depends on Ca2+ concentration and excitation wave length. The carried out analysis has revealed that Eu3+ ions form at least two different types of emission centers in the La1−x−yEuyCaxVO4 samples. The assumption is made that type I centers are formed by the Eu3+ ions in their regular positions in the crystal lattice, while the type II centers have complex structure and consist of Eu3+ ions, Ca2+ cations, and oxygen vacancies. It is established that Ca-induced defects are also responsible for additional excitation band near 400 nm.

Here, a single‐step, biomimetic approach for the realization of omnidirectional transparent antireflective glass is reported. In particular, it is shown that circularly polarized ultrashort laser pulses produce self‐organized nanopillar structures on fused silica (SiO2). The laser‐induced nanostructures are selectively textured on the glass surface in order to mimic the spatial randomness, pillar‐like morphology, as well as the remarkable antireflection properties found on the wings of the glasswing butterfly, Greta oto, and various Cicada species. The artificial structures exhibit impressive antireflective properties, both in the visible and infrared frequency ranges, which are remarkably stable over time. Accordingly, the laser‐processed glass surfaces show reflectivity smaller than 1% for various angles of incidence in the visible spectrum for s–p linearly polarized configurations. However, in the near‐infrared spectrum, the laser‐textured glass shows higher transmittance compared to the pristine. It is envisaged that the current results will revolutionize the technology of antireflective transparent surfaces and impact numerous applications from glass displays to optoelectronic devices.

The Sm-activated orthvanadate nanoparticles withLa(1-x)Sm(x)VO(4) (x <= 0.3) composition were synthesized by coprecipitation and sol-gel methods. XRD study has shown that synthesized samples are characterized by monoclinic or tetragonal structure as well as their mixture dependently on Sm concentration and methods of synthesis. Influence of method of synthesis on morphology of nanoparticles, their absorption, diffuse reflectance and emission spectra was observed and studied. Luminescence properties and diffuse reflectance spectra of the solgel nanoparticles are also depend on Sm concentrations. At least two types of Sm3+ centers were found by emission spectra. These centers have different excitation efficiency by light from the 350-450 nm spectral range. Structures of the centers are discussed taking into account crystal structure, possible defects, morphology of the synthesized nanoparticles and their phase compositions.

The results of both synthesis and study of morphology and optical properties of some bismuth containing phosphate - molydate ceramics as possible materials for creation of photocatalytic reactor are presented.

A comparative study is performed to explore the periodic structure formation upon intense femtosecond-pulsed irradiation of dielectrics with radially and azimuthally polarised beams. Laser conditions have been selected appropriately to produce excited carriers with densities below the optical breakdown threshold in order to highlight the role of phase transitions in surface modification mechanisms. The frequency of the laser-induced structures is calculated based on a theoretical model that comprises estimation of electron density excitation, heat transfer, relaxation processes, and hydrodynamics-related mass transport. The influence of the laser wavelength in the periodicity of the structures is also unveiled. The decreased energy absorption for azimuthally polarised beams yields periodic structures with smaller frequencies which are more pronounced as the number of laser pulses applied to the irradiation spot increases. Similar results are obtained for laser pulses of larger photon energy and higher fluences. All induced periodic structures are oriented parallel to the laser beam polarisation.

We herein report on the fabrication of high regularity, erasable and rewritable periodic surface patterns on silver metaphosphate glass (AgPO3) by means of ultrashort pulsed laser processing. The laser-induced periodic surface structures (LIPSS) are formed perpendicular to the laser beam polarization, exhibiting a periodicity similar to the laser wavelength. Notably, the so-formed periodic patterns can be readily erased upon further exposure to femtosecond laser irradiation under controlled conditions. This all-laser inscription and deletion protocol allows the reversible patterning of the phosphate glass surface by employing a single laser beam. Optical and Raman spectroscopy revealed that the formation of the periodic patterns and the erasing process do not cause any phosphate network modifications or structural damage on the glass, and thus, proving that the demonstrated reversible LIPSS process is entirely non-ablative. This remarkable feature could enable infinite cycles of the write/erase/re-write process on the same area of the glassy material, posing the AgPO3 glass as an important candidate for waveguides and optical responsive memory components of advanced photonic applications.

We report on the fabrication of highly ordered, multi-directional, complex surface structures that mimic the unique morphological features of certain species found in nature. In particular femtosecond laser pulses with various polarizations states, such as circular and vectorial, were utilized for structuring metal and dielectric surfaces. Experimental results showed that the direction of LIPSS in each case proved to be polarization dependent which gives as the flexibility to fabricate new and more complex surface structures.