A5038632507- Laser-induced spectroscopy and plasma
- Laser-Plasma Interactions and Diagnostics
- Analytical chemistry methods development
- Laser-Matter Interactions and Applications
- Mass Spectrometry Techniques and Applications
- Advanced Fiber Laser Technologies
- Chalcogenide Semiconductor Thin Films
- Nonlinear Optical Materials Studies
- Laser Material Processing Techniques
- Plasma Diagnostics and Applications
- Atomic and Molecular Physics
- Plasma Applications and Diagnostics
- Diamond and Carbon-based Materials Research
- Nonlinear Optical Materials Research
- Ocular and Laser Science Research
- Advanced X-ray Imaging Techniques
- Image Enhancement Techniques
- Advanced Measurement and Metrology Techniques
- Photochemistry and Electron Transfer Studies
- High-pressure geophysics and materials
- Electrodeposition and Electroless Coatings
- Spectroscopy and Quantum Chemical Studies
- Crystallography and Radiation Phenomena
- Copper-based nanomaterials and applications
- Quantum Dots Synthesis And Properties
Bulgarian Academy of Sciences
2012-2025
Georgi Nadjakov Institute of Solid State Physics
2012-2025
Luxembourg Institute of Science and Technology
2025
Czech Academy of Sciences, Institute of Physics
2020-2021
Extreme Light Infrastructure Beamlines
2019-2021
Sofia University "St. Kliment Ohridski"
2014
Silk fibroin (SF), the primary protein in silkworm silk, has emerged as a promising organic nonlinear optical material due to its unique combination of transparency, biocompatibility, and environmental sustainability. In this study, we investigate properties SF thin films using z-scan technique with femtosecond laser pulses (35 fs, 800 nm, 1 kHz). Our results reveal strong self-defocusing effect (negative refractive index) significant multiphoton absorption, demonstrating SF's tunable...
Highly polymorphic cobalt sulfide represents attractive material because of its unique electronic, optical, magnetic, mechanical and catalytic properties. Pulsed laser irradiation a solid CoS 2 target results in ablation deposition thin films on Ta Cu substrate, which were analyzed using scanning electron microscopy, Raman FTIR spectroscopy, X‐ray photoelectron high resolution microscopy diffraction. These complementary analyses revealed that the film consists parent cubic whereas exhibits...
Abstract Longitudinal sputtering hollow cathode discharge (HCD) used as active medium for lasing is studied by means of numerical modelling. Due to the longitudinal non-uniformities discharge, laser operation could be strongly affected. The non-uniformity mainly influenced dimensions cathode, in particular aspect ratio length/radius. To study geometrical features, a simulation model HCDs has been constructed using Plasimo modelling platform. allows in-depth studies plasma mechanisms and...
ELI Beamlines is a rapidly progressing pillar of the pan-European Extreme Light Infrastructure (ELI) project focusing on development and deployment science driven by high-power lasers for user operations. This work reports results commissioning run water-jet plasma X-ray source L1 Allegra laser, outlining current capabilities future potential system. The one developed in-house at Beamlines, designed to be able reach pulse energy 100 mJ 1 kHz repetition rate with excellent beam properties....
A novel sensor for detection of contaminants in fog using the Surface photo-charge effect is presented. The capable measuring presence contamination and giving a relative estimate its concentration. uses liquid layer which allows removing condensation at solid surface signal variation due to dynamics density variation. In addition, it able measure only contribution admixtures photocharge signal.
An impressive phenomenon of observed plasma instability and conical emission under the propagation ultrashort laser pulses in air is reported. The discussed novel findings demonstrating nonlinear effects are incapable to be explained standard spatiotemporal paraxial optics. Three main mechanisms investigated. first one related nonparaxial for waveguiding femtosecond pulses, second considers mechanism single filament formation at weak ionization. third demonstrates a new physical effect...
This study is focused on the selective laser removal of chlorine-containing corrosion products from artificially corroded samples copper, brass and steel. Its goal to find an efficient methodology for cleaning historical metallic objects. The treatment done with two sources: Q switched Nd:YAG generating nanosecond pulses at 1 Hz repetition rate in IR (1064 nm) green (510.6 spectral range, copper bromide vapor (CuBrVL) 20 kHz range. performed dry wet conditions. surfaces before after are...
Three main paths are being developed within the ELI research program for transforming driving laser pulses into bursts of bright short wavelength radiation: high-order harmonic generation in gases, plasma X-ray sources and based on relativistic electron beams accelerated plasma. For each these areas, dedicated beamlines built to provide a unique combination scientific community. The application has well-defined balance between fundamental science applications different fields technology....
Abstract Optical probing is an indispensable tool in research and development. In fact, it has always been the most natural way for humankind to explore nature. However, objects consisting of transparent materials with a refractive index close unity, such as low-density gas jets, are typical example samples that often reach sensitivity limits optical techniques. We introduce advanced method employing multiple passes probe through object increase phase sensitivity, relay-imaging between...
We present a new interferometric technique for gas jets density characterization employing Wollaston shearing interferometer. The distinctive feature of this setup is the double pass probe beam through target facilitated by relay-imaging object arm that images on itself and preserves spatial information. results in two-fold increase sensitivity at same time as enables with arbitrary distribution tomographic reconstruction. capabilities double-pass interferometer are demonstrated...
We propose a way of achieving efficient and robust second-harmonic generation. The technique proposed is similar to the adiabatic population transfer in two-state quantum system with crossing energies. If phase mismatching changes slowly, e.g., due temperature gradient along crystal, makes match for generation occur, then energy would be converted adiabatically second harmonic. As an technique, scheme presented stable variations crystal parameters, as well input light, length, intensity,...
Optical emission spectroscopy studies are reported of laser ablation plasma from an iron sulphide (FeS) target in vacuum. The is characterized with spatial and tempoal resolution. spectral observations used to calculate the electron parameters. temperature calculated by Boltzmann plot method number density, Stark broadening lines.
Orthodontic archwires are among the most important devices of fixed orthodontic therapy. Many types made available on market by various manufacturers with different elemental composition and structural characteristics. Knowing this information is when choosing a suitable archwire for particular stage treatment. The aim our study to characterize new type (TriTaniumTM, American Orthodontics) before their placement in oral cavity. To achieve aim, we used modern methods determining...
Abstract The emission characteristics of a scheme combining laser ablation as sample introduction source and hollow cathode discharge excitation are presented. spatial separation the material by is achieved optimizing gas pressure sample-cathode gap length. At these conditions current maximized to enhance analytical lines intensity.
We report on a kinetic model that computes the electron behaviour in hollow cathode discharge. It is part of PLASIMO toolkit and based Monte-Carlo technique. The tested by varying input parameters comparing output with obtained freeware Boltzmann equation solver BOLSIG+. results show gives reliable information about behavior electrons module applied to case discharge for laser applications. Analysis data its adequateness done. Future developments are discussed.
A new modified analytical scheme of laser ablation-hollow cathode discharge (LA- HCD) for elemental analysis is reported. The novelty the use a hollow with longitudinal slit. This slit enables registration axial species distribution in and decoupling signals. In this paper preliminary experiments on LA-HCD set-up are improved performance demonstrated by comparing it to stand-alone induced breakdown spectroscopy. results technique show enhancement excitation efficiency.
A kinetic model is reported computing the electron behavior in a hollow cathode discharge based on Monte Carlo technique. It part of PLASIMO modelling toolkit. The allows electrons to be closely followed while they travel and undergo collisions discharge. modulewas applied case HCD used as an excitation medium atoms obtained by laser ablation. Results are energy distribution function mean under typical conditions. output data future development its applications analyzed discussed.
Thin nanocrystalline Cu-In-S films are prepared by pulsed laser ablation in vacuum with Nd:YAG operating at 1064 nm on Si (100) substrates. As a target, CuInS2 quantum dots powder, synthesized sonochemical template-free colloidal approach and pressed to form pellet is used. The structure morphology of the deposited were studied employing X-ray diffraction, scanning electron microscopy, atomic force microscopy techniques. analysis thin revealed predominant cubic Cu1.7In0.05S phase. It has...
In this work, a plasma source for optical emission spectroscopy combining nanosecond laser ablation and DC hollow cathode glow discharge is presented. The capabilities of hybrid are demonstrated by analysis the spectra silver sample. obtained compared to those conventional stand-alone laser-induced sources. experimental results show that intensity atomic lines increases few fold in case source. registered line enhancement higher from high-lying energy states.
We studied the nonlinear properties of some most promising media for microelectronic applications - AlN and GaN. The refractive index n2 multiphoton absorption ß are measured by femtosecond z-scan method with virtual aperture.
Three main paths have been selected within the ELI Beamlines research program for transforming driving laser pulses into brilliant beams of short wavelength radiation: High-order harmonic generation in gases, Plasma X-ray sources, and sources based on relativistic electron accelerated laser-plasma. For each these areas, dedicated beamlines are built to provide a unique combination user community. The employment has well-defined balance between fundamental science applications different...
A scheme is reported for spectrochemical analysis combining sample introduction by laser ablation and additional excitation of the ablated material a hollow-cathode discharge. The optimal conditions allowing spatial separation two processes are determined. Under these conditions, enhancement analytical lines intensity in comparison with stand-alone laser-induced plasma observed.