Abstract Laboratory astrochemistry encompasses experimental and theoretical studies that contribute to our understanding of the universe by complementing and interpreting astronomical observations and modeling phenomena occurring within it. One of the most important questions in laboratory astrochemistry is the study of molecules in the universe and their interaction with radiation. This is related to the fundamental question of the origin of life on Earth. Astrochemistry plays a key role in explaining this mystery. Laboratory experimental astrochemistry studies are conducted using a variety of research instruments. Because most matter in the universe exists in plasma form, many of these instruments rely on plasma technologies. This paper presents a brief two research instruments based on laser-plasma extreme ultraviolet (EUV) and soft X-ray (SXR) sources. These instruments allow for simulations of molecular processes occurring in the universe under the influence of EUV radiation, such as the decomposition of complex molecules and molecular processes occurring in gas mixtures corresponding to the atmospheres of early planets or the synthesis of such molecules. This paper describes these instruments and the obtained research results. The construction of EUV laser-plasma sources is relatively simple and is based on commercially available devices and components, which allows research in this area to be carried out in small university laboratories.

Graphene oxide (GO) has recently attracted more attention for its own physical and chemical properties regardless of being initially seen only as an ideal candidate for the production process of single/few graphene layers. One of the most interesting forms of this material is a multilayer structure, sometimes called graphene paper, with a thickness approaching a value up to a few micrometers. We present and discuss the results of investigation on electronic structure of such a thick material produced by the improved Hummer's method and deposited on a metallic mesh. The samples were investigated by near-edge X-ray absorption fine structure spectroscopy (NEXAFS) around the carbon absorption edge. The NEXAFS results are supplemented with the output of the X-ray photoelectron spectroscopy (XPS) analysis for C1s and O1s lines and with the micro-Raman spectroscopy. There are still some discrepancies concerning the electronic structure of graphene oxide (GO), especially, when many individual GO sheets are stacked together as in the case under consideration. The samples were heavily functionalized by oxidation (the presence of carbonyl, epoxy, and hydroxyl groups). There are indications that the prepared samples tended towards the turbostratic form of stacking when annealed in vacuum at moderate temperatures between 100 degrees C and 500 degrees C. These changes were observed in both pi* and sigma* resonance areas. Surprisingly, the features of the NEXAFS spectrum of both the annealed and non-annealed samples resemble reasonably the theoretically determined structure of the density of states (DOS) of monocrystalline carbon. It could suggest a strong "graphitisation " process already in the sample preparation phase. The observed increase in the sample amenability to the environmental water with annealing temperature is discussed briefly. The results also deliver a clear support for the claims of room-temperature metastability of multilayer GO.

A near 1-keV photons from the Xe/He plasma produced by the interaction of laser beam with a double stream gas puff target were employed for studies of L absorption edges of period 4 transitional metals with atomic number Z from 26 to 30. The dual-channel, compact NEXAFS system was employed for the acquisition of the absorption spectra. L1–3 absorption edges of the samples were identified in transmission mode using broadband emission from the Xe/He plasma to show the applicability of such source and measurement system to the NEXAFS studies of the transition metals, including magnetic materials.

In this paper, the possibility of color controlling anodic titanium oxide by changing anodizing conditions of titanium in an ethanol-based electrolyte is demonstrated. Colored anodic titanium oxide was fabricated in an ethanol-based electrolyte containing 0.3 M ammonium fluoride and various amounts of deionized water (2, 3.5, 5, or 10 vol%), at voltages that varied from 30 to 60 V and at a constant anodization temperature of 20 °C. Morphological characterization of oxide layers was established with the use of a scanning electron microscope. Optical characterization was determined by measuring diffusion reflectance and calculating theoretical colors. The resulting anodic oxides in all tested conditions had nanotubular morphology and a thickness of up to hundreds of nanometers. For electrolytes with 3.5, 5, and 10 vol% water content, the anodic oxide layer thickness increased with the applied potential increase. The anodic titanium oxide nanotube diameters and the oxide thickness of samples produced in an electrolyte with 2 vol% water content were independent of applied voltage and remained constant within the error range of all tested potentials. Moreover, the color of anodic titanium oxide produced in an electrolyte with 2 vol% of water was blue and was independent from applied voltage, while the color of samples from other electrolyte compositions changed with applied voltage. For samples produced in selected conditions, iridescence was observed. It was proposed that the observed structural color of anodic titanium oxide results from the synergy effect of nanotube diameter and oxide thickness.

The term “laser microexplosion” has been introduced to stress the violent character of the optical breakdown by laser radiation under conditions of tight focusing. Generally, the starting phase of the breakdown has been neglected by the assumption of absorption triggered by the presence of damage precursors. The application of the plasticity–elasticity theory in the analysis of the dynamics of this phenomenon has not been extensively examined to date. This paper formulates a phenomenological model attempting to explain the creation of nanovoids in a soft matter under irradiation by a flux of extreme ultraviolet (XUV)/soft x-ray photons. The combined action of plastic deformation and dissociation waves on soft matter is found to be responsible for the material modifications. It is suggested that localized (volume≃λ3) abundance of energy, coming most likely from photon bunching, constitutes the real onset of the photo-ablative decomposition. It is shown that the coincidental presence of some small number of energy carriers (2–3 XUV photons in the considered case) in such a small volume triggers processes denoted from now on as a laser nanoexplosion. The effect is considered to be the first step in the optical breakdown followed by an intense material removal resembling, to some extent, a phase explosion.

We present a 2-D mapping of a sample thickness with nanometer accuracy employing a compact arrangement of near-edge X-ray absorption fine structure (NEXAFS) technique. A NEXAFS spectrum coupled with a scanning system was used to generate a 2-D thickness map of the TiO2 sample (anatase form) deposited on the top of a SiN membrane. The thickness values were retrieved from the experimental data by applying different methods of data processing. In the paper, the detailed analysis of the data processing methods and the identified sources of the errors show that the proposed procedure based on averaging two imperfect estimates reduces the error caused by the uncontrolled bias of the measured signals. This procedure was termed as the average one. The estimates from the proposed average approach and the standard absorption-jump ratio in the absorption edge vicinity were compared with the direct results obtained by applying scanning electron microscopy (SEM). The experimental arrangement of the NEXAFS spectroscopy system, the data acquisition method, as well as the possible error sources, are presented and discussed in detail.

A desktop tomography system, based on laser-interaction with a gas puff target, which results in efficient plasma formation emitting in the soft X-ray (SXR, λ = 0.1 - 10 nm) region, was developed at IOE-WAT (Warsaw, Poland). The system, coupled with an ellipsoidal condenser and a Fresnel zone-plate and working in the “water window” spectral range (λ = 2.3 - 4.4 nm) at the quasi-monochromatic He-like nitrogen spectral line (λ=2.88nm), allows acquiring images approaching a resolution of few microns. The development of such setup offers the possibility to obtain a reconstruction of three-dimensional images in a laboratory environment, without the involvement of large “photon facilities”. Details about the system and its optimization as well as some imaged samples will be presented and discussed.

A desktop laser-plasma double-stream gas-puff target soft X-ray (SXR) source, operating in the so-called “water window” spectral range (λ = 2.3–4.4 nm). was successfully employed to acquire 3D tomographic images in transmission mode, using a Fresnel zone-plate microscope. The microscope, operating at the He-like nitrogen spectral line, 2.88-nm wavelength, allows acquiring 3D SXR volumetric reconstructions with a resolution of a few microns. The development of a compact system offers the possibility to obtain 3D reconstructed images in relatively short time and in a laboratory environment, without the involvement of large “photon facilities”, such as synchrotrons or free electron lasers, however, with the modest volume resolution at this point. The possibility to obtain three-dimensional images in the SXR wavelength range using a compact, laser-plasma based system may be useful for material and life sciences, where it is required to visualize small features of the samples in 3D that are not visible with a single 2D image. Details about the equipment and the setup constructions as well as some imaged samples will be presented and discussed.

In this work investigations concerning interaction of intense, nanosecond EUV pulses with matter were performed. Various laser-produced plasma radiation sources were employed for creation of the driving EUV pulses. The sources were based on two different laser systems with pulse energies ranging from 0.8 J to 10J and pulse duration 4 ÷ 10 ns. They were equipped with the EUV collectors for focusing of the radiation. This way radiation fluence up to 0.5 J/cm2 in the interaction region was obtained. In our experiments solid material samples or gases injected into the vacuum chamber synchronously with the EUV pulses were irradiated. Irradiation of the gases resulted in ionization and excitation of atoms and molecules forming low temperature plasmas with a relatively high electron density. Emission spectra obtained from these plasmas, contained spectral lines corresponding to radiative transitions in atoms, molecules, atomic or molecular ions. For analysis of the EUV spectra numerical simulations were performed, using a collisional-radiative PrismSPECT code. For computer simulations of the molecular spectra measured in the UV/VIS range a LIFBASE and Specair codes were employed. This way ionization states together with various thermodynamic parameters were deduced. Irradiation of solid samples resulted in melting of a thin near-surface layer or, in some cases its ablation or even conversion to a low temperature plasma. It depended on physico-chemical properties of the material and its thickness. In case of organic polymers, usually ablation connected with fragmentation of the polymer molecules, took place. In case of thick samples of inorganic solids, a thin near surface layer was heated up to a high temperature exceeding melting or even boiling point. In most cases different kinds of micro- or nanostructures were created, modifying the surface morphology. Except the EUV interaction with solid materials, simultaneous EUV and the EUV induced plasma treatment was investigated. Plasmas were created in gases injected close to the exposed surface. Part of the EUV radiation was absorbed in the injected gas forming the low temperature plasma near the surface, while the other part of radiation, that was not absorbed, interacted with the surface material. This way additional atoms could be incorporated into the molecular structure of the exposed material, or reactive etching took place. Especially interesting results were obtained using molecular gases for creation the reactive plasmas.

BACKGROUND:The accessibility of the remineralizing ions in teeth's environment is essential for their incorporation into caries-affected dentin. Novel bioglass-reinforced materials capable of releasing fluoride, calcium and phosphates may be particularly useful in the tissue remineralization process. A novel restorative material, ACTIVA BioActive-Restorative (Pulpdent Corp., Watertown, USA), is a hydrophilic resin-modified glassionomer cement (RMGIC) enriched with bioglass particles and fortified with a patented rubberized polymer resin. Its application in restorative dentistry may be significant, promoting remineralization of carious lesions.OBJECTIVES:The aim of the study was to compare the fluoride ion release profiles from a bioglass-reinforced RMGIC, a conventional glass-ionomer cement (GIC) and a nanohybrid restorative polymer resin.MATERIAL AND METHODS:The quantity of fluoride ions released from ACTIVA, Ketac Molar Quick Aplicap and Tetric EvoCeram was assessed using a fluoride-specific electrode. The surface characteristics of the preand post-experimental specimens were studied using a scanning electron microscope (SEM) and confocal microscope. An X-ray powder diffraction (XRD) analysis was additionally used to examine the chemical compositions of the dental materials.RESULTS:The greatest quantity of fluoride ions was freed from the GIC specimens (20.698-54.118 ppm), followed by the bioglass-reinforced RMGIC (from 1.236 to 15.552 ppm) and nanohybrid polymer resin (0.370-1.148 ppm). The pre-experimental specimens of the bioglass-reinforced RMGIC were porous, while the post-experimental specimens were smoother with visible micro-cracks. The XRD analysis of the bioglass particles confirmed that the material was composed mainly of fluoride (27.70 mass%), silicon (15.62 mass%), aluminum (5.91 mass%), and calcium (5.40 mass%).CONCLUSIONS:The fluoride ion release profile of ACTIVA was lower than the GIC Keta Molar Quick Aplicap, but significantly higher than the nanohybrid restorative polymer resin Tetric EvoCeram.

In this work, a comparative study of extreme ultraviolet (EUV) induced low temperature SF6-based plasmas, created using two different irradiation systems, was performed. Both systems utilized laser-produced plasma (LPP) EUV sources. The essential difference between the systems concerned the formation of the driving EUV beam. The first one contained an efficient ellipsoidal EUV collector allowing for focusing of the EUV radiation at a large distance from the LPP source. The spectrum of focused radiation was limited to the long-wavelength part of the total LPP emission, λ > 8 nm, due to the reflective properties of the collector. The second system did not contain any EUV collector. The gas to be ionized was injected in the vicinity of the LPP, at a distance of the order of 10 mm. In both systems, energies of the driving photons were high enough for dissociative ionization of the SF6 molecules and ionization of atoms or even singly charged ions. Plasmas, created due to these processes, were investigated by spectral measurements in the EUV, ultraviolet (UV), and visible (VIS) spectral ranges. These low temperature plasmas were employed for preliminary experiments concerning surface treatment. The formation of pronounced nanostructures on the silicon surface after plasma treatment was demonstrated.

In this paper, results of surface modification, using a laser-produced plasma source of extreme ultraviolet, and the extreme ultraviolet induced low temperature plasmas, are presented. It was shown that irradiation of different materials by intense extreme ultraviolet pulses results in strong changes of the surface morphology. Examples of micro- and nanostructures obtained this way are presented. It was also demonstrated that a dual action of the radiation pulses and low temperature plasmas allows to modify a molecular structure of exposed materials.

Application of a compact laser plasmaLaser plasma source of soft X-raysSoft X-rays and extreme ultravioletExtreme ultraviolet (EUV) in imaging with nanometer resolution is demonstrated. The source is based on a gas puff target irradiated with nanosecond laser pulses from a small commercial Nd:YAG laser. Soft X-ray radiation in the ‘water window’ spectral range and EUV near 10 nm are generated efficiently without production of target debris. Nanoscale imagingNanoscale imaging of biological samples as well as micro- and nanostructures using transmission soft X-ray and EUV microscopy based on Fresnel optics and soft X-ray contact microscopy is demonstrated.

Low temperature plasmas induced by irradiation of molecular gases with extreme ultraviolet (EUV) pulses were studied. The EUV pulsed beams of high intensity, were formed using laser-produced plasma (LPP) sources, based on Nd:YAG laser systems and a double-stream Xe/He gas-puff target. The EUV beams were used for irradiation of small portions of gases, injected into a vacuum chamber synchronously with the radiation pulses. Low temperature plasmas produced this way in oxygen, nitrogen or sulfur hexafluoride gas emitted radiation in a wide spectral range. The corresponding EUV spectra were dominated by emission lines originating from singly charged, atomic ions. In case of spectra recorded in an optical range, emission lines, corresponding to radiative transitions in atomic or molecular species, were detected. Taking into account a Stark broadening of F I emission lines an electron density was estimated. Its value exceeded 1017cm-3, which is a few orders of magnitude higher comparing to plasmas produced in standard generators. Employing the SF6 – based plasmas an experiment concerning plasma treatment of a silicon surface was performed. A possibility to create different kinds of nanostructures was demonstrated.

The size and shape of biological particles are important parameters allowing discrimination between various species. We have studied several aerosols of biological origin such as pollens, bacterial spores and vegetative bacteria. All of them presented different morphology. Using optical size and shape analyser we found good correlation between light scattering properties and actual particle features determined by scanning electron and fluorescence microscopy. In this study, we demonstrated that HCA (Hierarchical Cluster Analysis) offers fast and continuous bioaerosol classification based on shape and size data matrices of aerosols. The HCA gives an unequivocal interpretation of particle size vs. asymmetry data. Therefore, it may provide high throughput and reliable screening and classification of bioaerosols using scattering characteristics. Keywords: bioaerosol classification, scattering, particle size and shape analysis, biological warfare agents’ detection, hierarchical cluster analysis (HCA)

In this paper, we present the first measurements of the partial spatial coherence of the EUV emission from xenon plasma in laser-plasma source, based on a double stream gas puff target. The Young double slit approach was employed to measure complex coherence factor of the EUV Xe emission at 13.5-nm wavelength in two orthogonal directions. The radius of coherence of ~60 μm was estimated at the distance of 2.1 m from the source. The number of coherently emitted photons was sufficient to demonstrate coherent imaging. Using partially coherent radiation from such source Gabor EUV holography was successfully demonstrated.

Allergic rhinitis, also known as hay fever is a type of inflammation which occurs when the immune system overreacts to allergens in the air. It became the most common disease among people. It became important to monitor air content for the presence of a particular type of allergen. For the purposes of environmental monitoring there is a need to widen the group of traditional methods of identification of pollen for faster and more accurate research systems. The aim of the work was the characterization and classification of certain types of plant pollens by using laser optical methods, which were supported by the chemmometrics. Several species of pollen were examined, for which a database of spectral characteristics was created, using LIF, Raman scattering and FTIR methods. Spectral database contains characteristics of both common allergens and pollen of minor importance. Based on registered spectra, statistical analysis was made, which allows the classification of the tested pollen species. For the study of the emission spectra Nd:YAG laser was used with the fourth harmonic generation (266 nm) and GaN diode laser (375 nm). For Raman scattering spectra spectrometer Nicolet IS-50 with a excitation wavelength of 1064 nm was used. The FTIR spectra, recorded in the mid infrared1 range (4000-650 cm-1) were collected with use of transmission mode (KBr pellet), ATR and DRIFT.

Radiation with shorter illumination wavelength allows for extension of the diffraction limit towards nanometer scale, which is a straightforward way to significantly improve a spatial resolution in photon based microscopes. Soft X-ray (SXR) radiation, from the so called ”water window” spectral range, λ=2.3-4.4 nm, which is particularly suitable for biological imaging due to natural optical contrast, providing much better spatial resolution than one obtained with visible light microscopes. The high contrast is obtained because of selective absorption of radiation by carbon and water, being constituents of the biological samples. We present a desk-top system, capable of resolving 60 nm features in few seconds exposure time. We exploit the advantages of a compact, laser-plasma SXR source, based on a double stream nitrogen gas puff target, developed at the Institute of Optoelectronics, Military University of Technology. The source, emitting quasi-monochromatic, incoherent radiation, in the “water widow” spectral range at λ = 2.88 nm, is coupled with ellipsoidal, grazing incidence condenser and Fresnel zone plate objective. The construction of the microscope with some recent images of test and real samples will be presented and discussed.

In this chapter the first demonstration of a desk-top EUV transmission microscopy at 13.8 nm, with a spatial (half-pitch) resolution as good as 50 nm in a very compact setup, is presented.