Slobodan Milošević

Institute of Physics, Zagreb

The metastable He atoms play an important role in atmospheric pressure plasma jet (APPJ) chemistry processes and in the plasma generation. This work presents cavity ring-down spectroscopy (CRDS) investigation of metastable helium atom (23S1) densities in a single electrode APPJ during sample treatment. A spatially resolved density distribution of a...

This study connects two fields of research: laser induced plasmas and nonequilibrium low-temperature plasmas by studying effects of preionisation, made by a single electrode atmospheric pressure plasma jet, on a laser induced breakdown in helium. Laser pulse (1064 nm, 4 ns pulse width, 5 Hz repetition rate) was focused into the helium jet flowing i...

An atmospheric pressure surface-wave microwave discharge and a kHz plasma jet are used to activate purified water. It is shown, that by varying the treatment distance and the initial Ar/N2/O2 mixture composition of the surface-wave microwave discharge the concentration ratio of NO−3 and H2O2 radicals created in the plasma activated water (PAW) can...

It is shown that plasma‐activated water (PAW) improves tolerance against combined low temperature and hypoxia stresses during germination. Due to PAW’s effect on the antioxidant system, PAW pretreatment mitigates the reducing effect on plant growth of the hydroponically applied NaCl. PAW pretreatment reduces the salt‐stress‐induced decrease of the...

T-2 and its major metabolite HT-2 toxin are naturally occurring contaminants in cereals, with the highest concentrations determined in oats. Because of their toxicity and resistance to conventional methods used in mycotoxin degradation, development of new effective procedures for reduction of T-2/HT-2 toxin levels is needed. The aim of this study w...

In this paper we compared the fast ICCD imaging with the newly developed diagnostic method that utilizes laser induced breakdown in plasma jet. Our helium plasma jet was powered by an 80 kHz high-voltage sine wave and propagated into the ambient air. Pulsed laser beam 1064 nm (4 ns pulse duration and 5 Hz repetition rate) was focused with the lens...

It is demonstrated that Cu ions can be used to control the ageing of plasmaactivated liquids (PAL) through the Fenton-type reaction, which acts as a competitor to the NO􀀀2 + H2O2 + H+ ! products reaction, and thus moderates the recombination of NO􀀀 2 ions. It is shown that the ageing dynamics is influenced by the type of Cu-ions source used, due to...

Nanometer-sized structures, surfaces and sub-surface phenomena have played an enormous role in science and technological applications and represent a driving-force of current interdisciplinary science. Recent developments include the atomic-scale characterization of nanoparticles, molecular reactions at surfaces, magnetism at the atomic scale, phot...

In this work we present results for the laser-plasma interactions near the water surface. We used atmospheric pressure plasma jet that was characterized in great detail previously [1] and the laser produced plasma [2]. Objective of this research was to investigate plasma-liquid interaction at atmospheric pressure. The plasma jet consists of a glass...

The absorption cross section from a rovibrational state of the lower electronic state to the rovibrational state of the upper electronic state (Lam et al. 1977, Chung et al. 1999) is and the spontaneous emission rate from the state to is D(R) is the electronic transition dipole moment,  is the molecular reduced mass, g(v-v tr) the line-shape funct...

We studied the formation and growth of thin Ge films deposited by pulsed laser ablation of a Ge target onto Si substrate at room temperature in helium protective atmosphere. 4 nsec long laser pulses at 1064 nm were applied at different pulse numbers. The morphology of the process was followed by atomic force microscopy (AFM) and grazing incidence s...

Surface of human hard dental tissues (enamel and dentine) was treated using a helium single-electrode atmospheric pressure plasma jet (APPJ) with the aim of enhancing surface properties of treated material. Modification of the enamel and dentine surface was observed using contact angle measurements and X-ray photoelectron spectroscopy. Even a short...

Gas-filled glass plasma electrodes coupled with high-frequency high-voltage generators are used in medicine and dentistry for more than a century. In recent literature, therapeutic effects of such procedure have been explained through topical bio-oxidative effects of ozone generated by the dielectric barrier discharge. The aim of this study was to...

In order to carried out the targeted modification of properties and achieve the desired effects by plasma treatment, it is necessary to determine and optimize the processing parameters such as the type of gas, gas flow rate, operating frequency, current, voltage, treatment time and distance between the electrodes and the substrate surface. In this...

This work presents a feasibility study of applying the Principal Component Analysis (PCA) to data obtained by Laser-Induced Breakdown Spectroscopy (LIBS) with the aim of determining correlation between different samples. The samples were antique bronze coins coated in silver (follis) dated in the Roman Empire period and were made during different r...

The efficiency of gas phase plasma at atmospheric pressure by using an electrical discharge in gas argon on the inactivation of microorganisms was examined. The gas phase plasma was applied to suspensions of pure cultures Escherichia coli 3014, Staphylococcus aureus 3048, Salmonella sp. 3064, Listeria monocytogenes ATCC 23074 and Bacillus cereus 30...

Objective: The aim of this study was to ascertain whether and how High Power Ultrasound (HPU) and Gas Phase Plasma (GPP) treatments affect the fatty acids composition and sensory properties of goat milk. Methodology: Determination of Fatty Acid (FA) composition was done with gas chromatograph equipped with flame ionization detector. Sensory analysi...

Optical emission spectroscopy was performed during atmospheric pressure plasma needle helium jet treatment of various toothbleaching gels. When the gel sample was inserted under the plasma plume, the intensity of all the spectral features increased approximately two times near the plasma needle tip and up to two orders of magnitude near the sample...

Pulsed cavity ring-down spectroscopy (CRDS) is a direct absorption, highly sensitive, versatile technique suitable for the analysis of a wide range of plasmas. CRDS belongs to a wide class of cavity-enhanced spectroscopies. This work briefly describes the basic principles of CRDS and summarizes the main literature specifically related to applicatio...

Laser plasma of Ti produced in vacuum was studied by optical emission spectroscopy. The plasma was produced in a single-pulse and a double-pulse mode of ablation in a collinear configuration of laser beams. It was shown that there is a significant enhancement in emission intensity in double-pulse mode. Moreover, depending on the delay time between...

In this paper, dynamics of double-pulse laser produced Titanium plasma was studied both directly using optical emission spectroscopy (OES) and indirectly from morphological properties of deposited thin films. Both approaches yield consistent results. Ablated material was deposited in a form of thin film on the Si substrate. During deposition, plasm...

Some applications of extremely non-equilibrium oxygen plasma for tailoring the surface properties of organic as well as inorganic materials are presented. Plasma of low or moderate ionization fraction and very high dissociation fraction is created by high frequency electrodeless discharges created in chambers made from a material of low recombinati...

The article reports on reciprocal influence between the sample surface and atmospheric plasma jet. This correlation is important since it changes plasma parameters and plasma itself, depending on the sample-material surface, presence of liquid or treatment distance. However, in experiments and treatments of surfaces with atmospheric plasma jets, th...

Objective: To study the effect of atmospheric pressure plasma (APP) jet as a potential accelerator of the degradation of hydrogen peroxide in bleaching gels which could lead to better and faster bleaching. Material and Methods: 25 pastilles of hydroxylapatite were colored in green tea for 8 hours and were randomly divided into five groups (n = 5)....

High power ultrasound (US) and cold gas-phase plasma (CP) are non-thermal processing technologies that maybe used in food processing industry. The main objective of this research was to study the effect of both treatments on selected yeasts (Rhodotorula spp. 74 and Candida spp. 86) in pure culture. Samples were treated by ultrasound with 57.50-, 86...

Low pressure inductively coupled plasma was investigated with a combination of two diagnostic techniques: catalytic probes and optical emission spectroscopy (actinometry). Three working gases were used: oxygen, oxygen–argon mixture and hydrogen. Concentrations of oxygen and hydrogen atoms were determined in a wide range of plasma parameters, with p...

Aims: The aim of this study was to investigate and compare two nonthermal techniques in the inactivation of moulds. Methods and results: High power ultrasound (20 kHz) and nonthermal gas phase plasma treatments were studied in the inactivation of selected moulds. Aspergillus spp. and Penicillium spp. were chosen as the most common mould present...

The present research focused on the optimisation of plasma process parameters for achieving hydrophilicity of raw cotton fabrics of defined structural characteristics. For this purpose surface activation of fabrics was carried out using low temperature inductively coupled RF (radio-frequency) plasma system with oxygen as non-polymerising gas. Low p...

Recent advances in vacuum sciences and applications are reviewed. Novel optical interferometer cavity devices enable pressure measurements with ppm accuracy. Innovative dynamic vacuum standard allows for pressure measurements with temporal resolution of 2 ms. Vacuum issues in construction of huge ultra-high vacuum devices worldwide are reviewed. Re...

In this paper, we report a comparison between the most commonly used single harmonics (sine voltage waveform) and the original multiple harmonics AC-driven atmospheric-pressure plasma jet. The designed multiple harmonics source was applied to a single-electrode plasma jet. In this research, we characterized and studied the advantages of a single-el...

Optical emission from laser produced plasma of GaAs was studied for various helium and argon background pressures. The pressure was changed in the range from 5×10−3 to 100 mbar. The time evolutions of selected atomic and ionic spectral transitions were measured and compared. Several different maxima in the temporal evolution of As and Ga optical em...

We used cavity ringdown spectroscopy to study how the laser ablation of various materials (graphite, aluminum and iron) influences production of 23S1 metastable helium in the regime of low pressure helium gas. Plasma was produced by nanosecond Nd:YAG laser at 1064 nm with irradiance from 0.8 to 10.9 × 109 W/cm2. Helium pressure ranged from 0.03 to...

This work analyzes the effect of nanosecond laser pulse deposition of GaAs in an inert atmosphere of Ar and He. The number of pulses and the gas pressure were varied and the effect on the nanoparticles formation was studied by scanning electron microscopy, grazing incidence small angle X-ray scattering, and atomic force microscopy. It is shown that...

A series of Ti-doped ZnAl2O4 (gahnite) samples with doping levels of 0, 1.8, 3.8, 5.4 and 11.6 at.% Ti in relation to Al were prepared by a sol–gel technique. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), EPR spectroscopy, UV–vis reflectance spectroscopy and photoluminescence (PL) studies. Diffra...

A series of Ti-doped ZnAl2O4 (gahnite) samples with doping levels of 0, 1.8, 3.8, 5.4 and 11.6 at.% Ti in relation to Al were prepared by a sol–gel technique. The samples were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), EPR spectroscopy, UV–vis reflectance spectroscopy and photoluminescence (PL) studies. Diffra...

Samples of PVC foils are exposed to an early afterglow of gaseous plasma created by an electrode-less RF discharge in predominant H-mode using Ar, H2 and O2 gases. Sample temperature is measured with a pyrometer while the presence of reaction products is determined with an optical spectrometer. The temporal evolution of major radiative species is m...

Laser-produced plasmas have many applications for which detailed characterization of the plume is requested. Cavity ring-down spectroscopy is a versatile absorption method which provides data on the plume and its surroundings, with spatial and temporal resolution. The measured absorption line shapes contain information about angular and velocity di...

Forward and backward moving atoms within the laser produced plasma plume were studied by means of a cavity ringdown spectroscopy. The plume was produced using a nanosecond Nd-YAG laser pulse illuminating stainless steel target in a vacuum or helium background gas. Measurements were done at pressures ranging from 10− 5 to 1 mbar. Atomic absorption l...

Characteristics of oxygen plasma during treatment of polymer graphite composite were monitored by optical emission spectroscopy. Plasma was created in a rather small volume of about 3×10 -5 m -3 within a quartz glass tube by an electrode-less radiofrequency discharge in the H mode. The discharge was established using an RF generator with the freque...

Highly reactive oxygen plasma with a very high dis- sociation fraction of oxygen molecules is often created in electrode- less discharges. The discharge runs either in the E or H mode. The E mode is obtained at low power while the H mode dominates at high power. The transition between two modes is easily observed by the naked eye or, even better, b...

Objectives: The aim of this study was to determine increase in transillumination of composite posts after etching and treatment in cold H2 plasma. Methods: Initial spectrophotometric measurement was taken for each of 20 FRC Postec composites used (Ivoclar, Schaan, Liechtenstein). Each post was illuminated with LED lamp LUX.V ST. HEX LAMB. DENT-BL....

Optical emission spectroscopy was used to monitor the evolution of chemical reactions taking place on the surface of semicrystalline polypropylene during oxygen plasma treatment. The optical spectra were continuously acquired during treatment at different pressures (20-140 Pa). The time evolution of different excited radicals (O, H, CO, OH, and CH)...

Ablation using very short pulses has shown a great promise in facilitating the growth of complex multi-element films with stoichiometries matching those of their parent materials. GaAs is an important material in the electronic and opto-electronic industries and due to its compound structure it is an intriguing candidate for pulsed laser deposition...

The deposition of amorphous hydrogenated carbon thin films by inductively coupled radio frequency (IC RF) pure methane plasma and its subsequent removal by IC RF pure oxygen plasma have been studied within a cylindrical glass tube. Both processes were simultaneously monitored by optical emission spectroscopy, light transmission through thin film de...

Laser ablation of titanium in vacuum was performed using single- and dual-pulse regime in order to study crater formation. Crater profiles were analyzed by optical microscopy. It was found that the repetition-rate plays an important role in a process of laser ablation. The drilling is most effective for the highest repetition-rate. For the same tot...

Aim: Today's dental posts are continually adapted for easy application in minimal time. Present study investigated optimal conditions needed for etching of FRC Postec (Ivoclar, Schaan, Liechtenstein) with low pressure plasma. Materials and methods: FRC Postec composite posts were etched using low pressure inductively coupled radio frequency hydroge...

A highly reactive oxygen plasma was applied for the oxidation of aluminium foils. The plasma was created within a radio-frequency discharge operating at a power of 300 W and a frequency of 27.12 MHz. Samples of Al foils with dimensions of (20 × 40) mm were placed into the discharge chamber. During the treatment of the foils with oxygen plasma, the...

Ethanol vapor plasma has a high potential in various applications such as hydrogen productions [1], materials surface modifications or for nanostructures growth [2]. RF inductively coupled plasma allows achievement of various plasma conditions by change of plasma device design characteristics. In the present work we have applied OES technique for c...

Inductively coupled RF water vapour plasma generated in a linear glass tube was studied by means of optical emission spectroscopy. Low pressure water vapour plasma was created by an 8 turn coil with an EM field oscillating at 13.56 MHz. Various total pressures (5–14 Pa) and discharge powers (100–300 W) were investigated. Excitation temperatures (be...

Objectives: The contemporary dentistry attempts to simplify every procedure to minimize mistakes and shorten the time of application. The object of this study was to determine whether pretreatment of FRC Postec (Ivoclar Vivadent, Schaan, Liechenstein) with plasma in laboratory can replace etching with 37% orthophosphoric acid. Methods: Low pressu...

The plasma plume induced by dual-pulse laser ablation of a titanium target in vacuum was analyzed by the technique of cavity ringdown spectroscopy (CRDS). Large Doppler-splitting of the absorption spectral lines was observed which is due to increase of the velocity components parallel to the optical axis and specific features of the CRDS measuremen...

The laser-induced plasma plume of a Ti target in vacuum is probed by the technique of cavity ringdown spectroscopy. A model is developed to perform a forward convolution of atomic absorption line profile measurements. The model accounts for laser-induced plasma characteristics such as anisotropy of the plume and velocity distributions of the ablate...

Low-pressure inductively coupled oxygen plasma sustained within a linear glass tube was loaded by acetone vapours and characterized by means of the optical emission spectroscopy. Both spatial and temporal emission measurements were performed. Spectra consist mainly of the CO molecular bands which were used to characterize the plasma conditions. Spe...

Inductively coupled RF oxygen plasma generated by inductive coil wrapped around a linear glass tube is studied. Images of plasma properties in the linear reactor are presented. Plasma diagnostics was performed by spatially resolved optical emission spectroscopy.

Inductively coupled oxygen plasma is widely used for material processing. Optical emission spectroscopy using fast miniature fiber spectrometer was used for plasma characterization and process monitoring. The images of plasma and accompanying spectra during interaction with aluminium foil are presented.

Dynamics of laser-induced plasma plume studied by cavity ring-down spectroscopy (CRDS) was simulated by a numerical model. Velocity distribution and anisotropy of the plume with temporal and geometrical characteristics of CRDS were included. Behavior of spectral lineshapes was studied in respect to various experimental parameters.

Low temperature plasmas have a broad area of applications for treatment of various materials which points to the need of real time plasma characterization during processing [1,2]. Inductively coupled plasmas are of particular interest since details of the inductive coil design and its surrounding can be used to influence plasma content. Water plasm...

Optical emission spectroscopy was applied for the characterization of inductively coupled RF oxygen plasma at pressures between 10 and 300Pa. The plasma was generated with an RF generator at a frequency of 27.12MHz and output power of 300W. Spectra were measured in the range 200–1100nm by an optical spectrometer. At high pressure, the main spectral...

Surface effects during plasma activation of poly(p-phenilene sulphide)—PPS have been studied. Samples that were exposed to weakly ionized highly dissociated oxygen plasma created an inductively coupled radiofrequency discharge with the power of 100W. The electron density and temperature were measured with a double Langmuir probe and were 4×1015m−3...

We report the observation at thermal energies of the energy pooling collisions 6P + 6P in Cs vapour excited by a laser diode. The rate coefficients of the process Cs(6P3/2) + Cs(6P3/2) → Cs(7P3/2, 1/2) + Cs(6S1/2) are measured for the first time.

Various types of standing or moving striations and transition phenomena appear in inductively coupled radio-frequency molecular (or noble gas) plasmas. When plasma is loaded with various vapours of easily evaporated liquids such as ethanol, acetone or water, the observed phenomena could be substantially modified. We present the study of such phenom...

A study on oxygen-plasma treatment of ink-jet paper is presented. Paper was exposed to a weakly ionized, highly dissociated oxygen plasma with an electron temperature of 5 eV, a positive-ion density of 8 × 1015 m−3 and a density of neutral oxygen atoms of 5 × 1021 m−3. Optical emission spectroscopy (OES) was applied as a method for detection of the...

We use and develop various techniques such as optical emission spectroscopy, laser-induced breakdown spectroscopy, and cavity ring-down spectroscopy to characterize laser-induced and radio-frequency inductively coupled plasmas, and their combinations. Critical comparison of techniques is presented in the case of plasma treatment of various metallic...

Optical emission spectroscopy was applied for plasma characterization during sterilization of substrates contaminated with bacteria. The amount of 10{sup 10}/ml cells of Escherichia coli was carefully applied to glass substrates and exposed to oxygen plasma glow discharge at different pressures between 30 and 200 Pa. Plasma was created in a glass d...