Ukrainian synchrotron and neutron users' community (USyNC) is a very young organization that is just taking the first steps towards official registration. Ukrainian synchrotron and neutron radiation users` organization was officially founded at the meeting on November 2, 2023. There are 70-80 active users of synchrotron radiation in Ukraine, based or associated with Ukrainian institutions. At...
The electronic band structure holds the key to understanding the properties of quantum materials, as well as the mechanisms behind quantum phenomena like superconductivity and other electronic orderings. In this talk, I will briefly review our results in this area and highlight cases where synchrotron experiments play a crucial role in determining the real electronic band structure, thereby...
The SOLARIS synchrotron in Krakow, Poland, is a third-generation light source operating at 1.5 GeV electron energy. The project was officially initiated in 2010, the first synchrotron light was observed in 2016, and the first user experiment was performed in 2018. At present, SOLARIS Centre offer access to 10 research instruments at seven beamlines and two cryo-electron microscopes, and is...
PolyX (polychromatic X-rays and polycpaillary X-ray optics) is a newly developed bending magnet beamline at SOLARIS National Synchrotron Radiation Centre in Kraków, Poland. SOLARIS is a 1.5 GeV synchrotron (circumference 96m) build with unique collaboration between MAX IV Laboratory and Jagiellonian University [1].The beamline is dedicated to X-ray microimaging and X-ray spectromicroscopy [2]...
The ASTRA beamline at the SOLARIS synchrotron (Krakow, Poland) is a relatively new bending magnet beamline, having been open for user operation for just 14 months. As suggested by its name (ASTRA - “Absorption Spectroscopy beamline for Tender energy Range and Above”), it is an X-ray absorption spectroscopy (XAS) beamline. The photon energy range covered by ASTRA extends from 1 to 15 keV,...
X-ray spectroscopy experiments often require high-brilliance sources of X-ray radiation, provided by synchrotron or X-ray free electron laser (XFEL) facilities. However, acquiring access to such facilities is a complex procedure, which involves proposal application, long wait for the beamtime and travel expenses. Recent advances in the compact X-ray sources allowed for development of...
V.V. Kondratenko, E.N. Zubarev, Y.P. Pershyn*, I.A. Kopylets+, A.Yu. Devizenko, L.E. Konotopsky, V.A. Sevryukova, V.S. Chumak
X-ray Optics Group at National Technical University “Kharkiv Polytechnic Institute”
*pershyny@ukr.net +iakop@ukr.net
Our group has experience in the fabrication and study of multilayer coatings, which are mainly used in X-ray optics as multilayer X-ray...
‘Seeing means believing’ as the old axiom says. Every year around 50 000 scientists worldwide use X-ray photon beams at synchrotron and X-ray Free-Electron Laser (XFEL) facilities to image the structure and motion of matter. X-ray studies on protein crystallography and X-ray driven catalysis in biomolecules became reality with the development of synchrotron light sources. The advert of XFELs...
Free-Electron Lasers are versatile research tools that provide powerful (up to TW-order) and short (down to sub-fs-order) X-ray pulses.
European XFEL is an international facility dedicated to deliver such pulses to users
In this presentation I will introduce listeners to the basics of FEL Physics. We will discuss capabilities of the European XFEL facility in both nominal and special...
The FXE instrument enables ultrafast pump–probe experiments on timescales below 100 femtoseconds, catering to a broad scientific user community. FXE features two independent secondary X-ray emission spectrometers alongside a 1-Mpx detector for scattering studies. Its primary research focuses on the dynamic studies of chemical and biochemical reactions in liquids, as well as various solid-state...
The atomic structure of the thin Fe layer after sub-ps pulsed laser annealing has been studied by time-resolved X-ray diffraction [1]. The laser pulse energy is transferred to the lattice within about 1 ps due to the strong electron-phonon coupling. This rapid heating leads to ultrafast melting. However, solid-solid structural transformations occur below the threshold of complete melting. At...
Photoelectron spectroscopy using excitation by hard X-rays in the range of 2.5-10 keV (HAXPES) is rapidly developing at synchrotron light sources worldwide. Its comparatively large probing depth (10-30 nm) makes it a powerful tool for the study of complex materials, magnetic (buried) nanostructures, device-like structures, and catalytic interfaces.
The P22 beamline at PETRA III is a...
In October 2024, P66 vacuum ultraviolet (VUV) time-resolved luminescence beamline marks three years of successful operation. Inheriting its main features from previous SUPERLUMI beamline at DORIS III storage ring [1], P66 is requested by leading scientists from more than 30 scientific groups around the world. Excitation and emission energy scans of the luminescence intensity within a unique...
Wide bandgap zirconia attracts considerable attention because of its mechanical, dielectric, thermal and corrosion properties as well as its broad luminescent spectrum. This latter can be tuned by doping with various elements. Doping with yttrium stabilises tetragonal and cubic zirconia structures at room temperature. Simultaneously, zirconia intrinsic luminescence changes because additional...
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Our research explores the possibility to enhance the stability and functionality of perovskite solar cells through the encapsulation of these materials with isomorphically substituted calcium hydroxyapatite (Ca10-zXz(YO4)6(OH)2, where X = Ni, Fe, Cu; Y = V, P) as a transparent encapsulating layer. Building upon recent findings on the electronic structure of calcium apatites, we aim to optimise...
In 2023, the global average temperature got 1.52degC higher than that of pre-industrial time, already exceeding the +1.5degC limit set by IPCC. There won’t be any winner in the fight against global climate change. If we are unable to cooperate now, we will all fall down, going into the future of catastrophic starvation, water and energy shortage, plague, anything horrible you can imagine....
Over the past decade, metal halide perovskites (MHPs)—a novel class of water-soluble semiconductors with an exceptional combination of unique properties—have garnered significant attention for their potential in a wide range of optoelectronic devices. These include solar cells, detectors for optical and ionizing radiation, light sources, lasers, and various optoelectronic sensors.
As...
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Two-dimensional hybrid perovskites have attracted considerable interest for combining Van der Waals properties like quantum confinement and reduced dielectric screening with the structural tunability of perovskites. In these materials, both layer composition and sublayer number can be varied, impacting quantum confinement effects. These structures are often modeled as periodic quantum wells...
The study of hybrid organic-inorganic perovskites has rapidly emerged as one of the fastest-growing research areas in materials science over the past decade. Our study shows that aziridinium cation (AzrH) is able to support 3D perovskite structure of (ArzH)PbHal3 (Hal = Cl, Br, I). Highly reactive species of aziridinium was stabilized in 3D lead halide frameworks and was found to be a small...
Layered 2D hybrid organic-inorganic perovskites (2D-HOIPs) exhibit a distinctive array of properties, including remarkable structural flexibility, enhanced resistance to moisture, and optoelectronic characteristics valuable for practical applications. Chiral HOIPs can widen the scope of possible applications towards detection and generation of circularly polarized light. We developed a series...
Metal halide perovskites (MHPs) have become attractive materials for light-matter interaction, and particularly for quantum optic devices [1]. Their advantages include straightforward fabrication by chemical synthesis, a broad bandgap tunability with the composition, the high emission efficiencies, and the high excitonic binding energy. Consequently, low dimensional MHPs have been incorporated...
In 2015, Park and colleagues generated the first room temperature perovskite based single-photon source using all-inorganic CsPbI3 quantum dots (QDs). Since then, quantum light emission from a variety of perovskite nanocrystals (PNCs) has been demonstrated at both ambient and cryogenic temperatures. Despite the remarkable features of PNCs, the use of PNCs is restricted by their photostability....
Advances in material engineering have demonstrated the high stability and low toxicity of tin-based perovskites, presenting an excellent lead-free alternative. Consequently, an ab initio study was conducted to investigate the structural, electronic, and optical properties of the tin-based perovskite oxides ASnO3 (A = Ba, Ca, Sr, Mg). The structural parameters showed highly consistent results...
Two-dimensional molybdenum disulfide (MoS2) has attracted significant interest in the field of optoelectronics owing to its direct bandgap, tunable optical properties and the potential for realizing van der Waals heterostructures. It is considered one of the most successful transition metal dichalcogenides, thanks to its exceptional mechanical, electronic, optical, and transport properties...
In the last decade, the rise of monolayer (ML) transition metal dichalcogenides (TMDs) has changed the paradigm for the coupling of two-dimensional materials to a well-established platform without the constraints imposed by epitaxies such as crystal-lattice match or chemistry compatibility. The employment of semiconducting monolayers has resulted in several applications in different fields...
Nanolayers of transition metal dichalcogenides are interesting as 2D materials for novel nano-optoelectronics. Molybdenum disulfide is one of the most studied. At the limit of the monolayer, whose thickness is ~0.7 nm, molybdenum disulfide possesses a direct optical bandgap leading to an intense excitonic photoluminescence (PL) and a bandgap value of about 1.88 eV (660 nm) at room temperature....
Two-dimensional (2D) materials like MoS₂ hold immense promise for novel optoelectronic and nanophotonic applications. However, their practical implementation is often hindered by limited photoluminescence and Raman efficiencies. Plasmonic enhancement using metal nanoparticles provides an effective approach to overcome these limitations by enhancing light-matter interactions in these materials....
Molybdenum disulfide (MoS₂), a two-dimensional transition metal dichalcogenide with a direct bandgap in its monolayer form, presents significant potential for a wide range of applications in optoelectronics. The heterostructure formed by combining MoS₂ with gallium nitride (GaN), a wide-bandgap semiconductor characterized by high electron mobility, thermal stability, and favorable optical...
The idea of using quantum dots (QD) to extend the spectral sensitivity and improve the efficiency of solar cells was first put forward by Aroutiounian et al. (J. Appl. Phys. 89, 2268, 2001). QDs indeed provide several useful knobs in photovoltaics, such as tuning the bandgap for a certain spectrum and concentration, realizing current-matched multiple junction cells, and improving radiation...
Elemental substitution in Cu₂ZnSnS₄-like chalcogenides opens up the potential to create alternative low-cost photovoltaic and thermoelectric materials with tunable properties. The method of "green" synthesis in aqueous solutions, based on the protocol previously proposed for CZTS [1], has been used to obtain Cu₂NiSnS₄ (CNTS) nanocrystals (NC). This method opens up possibilities for non-toxic,...
Spinels present large compositional diversity and property tunability and thus are of interest to many technology fields. The cubic structure and broad optical transparency associated with a large band gap of the Mg and Zn aluminate spinels make these materials particularly attractive for optical applications.
MgAl2O4 and ZnAl2O4 in a diversity of forms, from powders prepared by the...
Beta gallium oxide (β-Ga₂O₃) thin films have attracted considerable research interest due to their wide bandgap, high thermal and chemical stability, and high breakdown voltage making them suitable for power electronics, UV photodetectors, solar cells, and sensors [1]. In this work, β-Ga₂O₃ thin films were deposited on c-plane sapphire substrates via spray pyrolysis [2]. This approach is...
Ga2O3 is an ultra-wide bandgap semiconductor that enables the fabrication of solar-blind UV-C radiation detectors without the need for filters to reject visible, UV-A and UV-B daylight. Applications of this type of detector include the monitoring of sanitization processes and hydrogen combustion, along with the early detection of corona effects in power grid lines and high-voltage...
The p-type emerging materials for photovoltaics such as inorganic chalcogenides and organohalide perovskites or other materials for renewable and sustainable energy applications in thin film or powder form are often reported with misleading/wrong optical and structural parameters. Thus, the credibility and significance of many published works should be questioned by the readers. Following a...
In this talk, two iterative cycles are proposed to obtain the solar cell parameters: the saturation current, the light current, the series resistance, the parallel resistance and the ideality factor. Obtaining these parameters is of scientific and technological importance, since they provide valuable information for their research, improvement and commercialization.
Gallium nitride (GaN) is a highly effective semiconductor for a wide range of applications, including light-emitting diodes (LEDs) and laser diodes (LDs) [1]. However, the thermal, optical, and electrical properties of GaN vary significantly depending on the deposition parameters employed. Temperature control at each stage of deposition, such as steady state, accumulation of Ga...
Author: Dewasthali Tejaswi Ramchandra
Co-author: Suman Rani
Garnets have been receiving attention lately considering to their potential to improve the efficiency of photonic devices. As a host, garnets have exceptional chemical and physical stability, which makes them dependable options for a range of applications in materials science, electronics, and optics. This work examines the...
Author: Shruti Bakshi
Co-Author: Suman Rani
Transparent conductive materials that are conducted and transmissive are an important aspect in the field of optics and electronics as they play a major role in modern optoelectronic devices. Zn1-xMgxO (x = 0.01) thin films are such material that lies in the category of Transparent conducting materials exhibiting exciting properties like low...
Copper Zinc Tin Sulfide (CZTS) thin-film solar cells have gained significant attention as a promising alternative to traditional photovoltaic technologies, owing to their use of earth-abundant, non-toxic materials. A critical factor in enhancing the efficiency of these cells is the incorporation of a Back Surface Field (BSF) layer. The BSF layer plays a key role in minimizing electron...
Scanning Probe Lithography (SPL) is a versatile technique for prototyping planar nanostructures with simultaneous in situ characterization. Using a nanoscale tip, surfaces can be mechanically or electrically modified to create predefined patterns, either through direct modification or thin resist layer masks. Additionally, interference and plasmon lithography allow for the efficient generation...
Direct laser writing (DLW) has become a leading technology for creating diffractive optical elements (DOE), particularly for submicron structures. As subwavelength optical devices such as photon sieves and metadevices are developed, the need for precise micro- and nanoscale structures grows. Conventional optical systems, limited by the diffraction limit, struggle to form elements smaller than...
The study presents an analytical model for the switching voltage and gain factor of a CMOS inverter with 2D nanochannel transistors. The derived expressions enable the modeling of these two fundamental parameters of the device, which serves as the foundation for logic elements in contemporary nanoelectronics. The feasibility of creating efficient inverters with a high gain factor based on...
Yann Amouroux represents Optica, the international society dedicated to advancing Optics and Photonics Worldwide.
In this non-technical talk, he will discuss career development, how learned societies encourage international collaboration, and some of the emerging trends in optics and photonics.
The world is changing rapidly, with constant challenges taking place; what are the opportunities...
In the present talk, I will review the latest results which we have obtained dealing with ultrafast linear and nonlinear acoustics. I will describe our findings related to the excitation of non-destructive shock waves, as well as some results related to the superposition of shock waves for optimum laser excitation.
The impact of microscale particles with a surface is of fundamental importance in surface coating technologies such as laser-induced forward transfer or cold spray. Successful bonding between the particles and the substrate requires impact velocities higher than the so-called critical adhesion velocity. Previous experimental and theoretical results showed that the critical velocity is a...
Silicon nanowires have unique thermophysical and optical properties that suit various applications, including sensors, energy systems, and semiconductor industries. The optical properties of silicon nanowires can vary significantly depending on their synthesis method and the initial parameters of the crystalline material, both of which have a substantial impact on the resulting morphology....
We report the quadratic nonlinear optical responses of noble metal nanoparticles with various size and shapes, and their corresponding hyperpolarizability β values as measured via the Harmonic Light Scattering technique at 1.064 µm.
First we investigate the influence of surface area of gold and silver nanospheres and nanorods on their β values, and explore the validity limit of their purely...
Since its discovery in 1928, Raman spectroscopy has become a powerful tool for molecular identification due to its ability to detect molecular fingerprints. It is widely applied in various fields such as pharmacology, food analysis, and mineralogy. The integration of Raman spectroscopy with optical microscopy has advanced hyper-spectral imaging, enabling detailed spectral acquisition within...
In multiply scattering media, there is the possibility of light lasing without optical resonator. This phenomenon is possible due to the formation of positive feedback resulting from the repeated extension of the path of a scattered photon in the active region and called random lasing.
The main parameters that influence the occurrence of random lasing in the active medium are: the...
This work investigates random lasing (RL) in confined clusters of strongly scattering media using Monte Carlo method (MCM). The study include calculations of the photon distribution for both pumping and RL within such clusters, as well as the visualization of media containing these clusters.
The MCM demonstrates that the maximum photon density of RL is concentrated at the center of the...
The development of integrated optoelectronics requires the creation of lasers with minimum sizes which would be acceptable for integration into the corresponding optoelectronic circuits. The most suitable for this purpose are waveguide planar lasers, which are integrated with waveguides and other devices of the optoelectronic circuit. At present, most attention is paid to films based on rare...
Mid or Near-IR Mode-Locked Lasers offer several advantages over simple Continuous-Wave (CW) Lasers due to their unique operational characteristics and significant commercial applications. Mode-locked lasers typically generate ultra-short and ultra-fast pulses with very high peak powers and repetition frequencies, which are essential for a wide range of applications such as nonlinear optical...
Reciprocal Asymmetric Transmission (RAT) has attracted attention of the metamaterial, photonic crystal, and artificial chirality communities since 2000’s. Initially, RAT has been understood as the difference in transmission when the structure with broken spatial inversion symmetry is illuminated by the same linearly or circularly polarized wave in forward and backward (i.e., opposite)...
Two-dimensional (2D) materials offer unique opportunities for photodetection, light emission, energy harvesting, and enhanced light-matter interactions. Even more interest brings the artificially engineered 2D micro- and nanostructures with on-demand properties paving the way towards a plethora of specific applications and devices including lensing, holography, imaging, polarimetry,...
Hyperbolic metasurfaces are known for their dispersion and polarization properties, such as negative refraction, hyperlensing, enhanced spontaneous emission, etc [1]. The surface waves localized at hyperbolic metasurfaces are called hyperbolic plasmon-polaritons and exhibit a lot of potential applications for planar technologies [2].
In this work, we analyze the dependencies of the spectral...
Designer gratings, also known as metagratings, can be tuned to preform various kinds of tasks, such as amplify deflection in a particular diffraction order, increase or decrease transmission and reflection [1]. A typical task for various kinds of coatings is to reduce reflection from a surface. Inspired by this, we set out to design a single-layer silicon metagrating as an antireflection cover...
Chirality is used to describe an object that is not superposable on its mirror image. Despite having the same chemical structure, most chiral molecules show significant differences in biological activity, being the poison or the drug depending on the handedness. The main difficulty during the measurement of chiral substances is the need to detect extremely weak chiroptical signals from a small...
In recent years, research utilizing Mixed Reality (MR) has garnered attention in medical fields, particularly in radiology. By rendering data acquired from X-ray CT and MRA in 3D and aligning it with the real-world environment, MR can be applied to support diagnostics, simulate surgeries, and assist in medical procedures. However, conventional multi-planar reconstruction (MPR) images of...
Backscattered X-ray imaging is a nondestructive inspection that uses X-rays scattered backward from an object.
Compared to X-ray transmission imaging, backscattered X-ray imaging has the advantage that the source and detector can be placed on the same side of the object. It is currently used to inspect thick objects and structures.
Although material decomposition methods using X-ray...
So far, the CT-imaging reconstruction algorithm mainly use Fourier transform method and ART(Algebraic Reconstruction Technique)method. Especially Fourier transform method is based on that the sinogram is linear for X-ray(single color)absorption coefficient on the object materials. However strictly speaking, usual CT use White X-ray, then the sinogram is not linear for X-ray absorption...
In recent years, radiotherapy using diagnostic imaging devices has been used in the medical field. In the treatment of scalpels and other instruments that approach the body, it is now possible to compare CT images for treatment planning and immediately prior to treatment to pinpoint the scalpel insertion. This enables more accurate alignment than the previously possible adjustments made by...
Many of the various products in the world are composed of multiple materials. For example, snacks such as chocolate are sold packed in plastic or paper, and smartphone charging cables have metal power lines covered with nylon. These products can be distinguished by the eyes, but some composite materials cannot.
In X-ray imaging by photon counting using a CT system, X-rays pass through the...
Cadmium Telluride (CdTe) is one of the excellent semiconductor detector materials. However, the long-term stability of the electrode on CdTe has been relatively understudied. CdTe detectors with Cu-electrode were fabricated to analyze stabilities of the junction between the electrode and the crystal. The fabricated detectors demonstrated excellent rectifying properties after electrical aging,...
Semiconductor radiation detectors with high energy sensitivity are primarily being developed, but there is a demand for semiconductor detectors that can handle low energy levels of around 30 keV or less. Therefore, we propose gallium nitride (GaN) as a new semiconductor detector material, aiming for detectors useful in the low energy range of approximately 10 to 26 keV. GaN has a large...
CdTe as a semiconductor has advantages when used as a radiation detector, such as sensitivity to high energy and the ability to operate at room temperature. However, the disadvantage is that the charge collection efficiency is lower than that of Si and Ge, and a high voltage must be applied to collect a sufficient amount of charge. Therefore, it is necessary to suppress the leakage current...
In X-ray imaging, light elements are transmitted through light elements and scattered and absorbed by high-density metals, so the transmitted image shows the metal portions well. In contrast, neutron imaging transmits light elements such as hydrogen through metal and is scattered and absorbed by light elements such as hydrogen, so that the transmitted image shows the areas containing light...
Thallium bromide (TlBr) is a semiconductor material with a band gap of 2.68 eV. TlBr has a large atomic number (81, 35) and a high density (7.56 g/cm 3), and therefore exhibits high absorption efficiency for X-rays and gamma rays. Due to these excellent physical properties, TlBr is being researched as a suitable material for semiconductor detectors operating at room temperature. TlBr has a low...
In quantum optics it is widely believed that all measurements with coherent states of light and their statistical mixtures can be explained without the need to quantize the electromagnetic field. Quantum states that do not satisfy this condition are considered to be nonclassical. Nowadays, optical nonclassicality is often considered as an important resource for creating quantum entanglement...
An optical state is considered nonclassical if its density operator cannot be represented as a statistical mixture of coherent states. This definition renders prominent phenomena such as sub-Poissionian statistics of photon counts or quadrature squeezing nonclassical. However, determining whether an optical state is nonclassical is a challenging task since it requires tomographic...
Gaussian boson sampling (GBS) (see Ref. [1]) is a promising quantum computing model that exploits photonic systems to perform computations beyond the reach of classical methods. A crucial aspect of GBS is the detection of photon patterns at the output of an interferometer. However, most experiments rely on on-off detectors that can only identify whether photons are present, without resolving...
Quantum communication is a rapidly developing field focused on enhancing the security of communication protocols and new methods of information exchange. These techniques use quantum light propagating through glass fibers or free space as the information carrier. While the free-space channels are useful in many practical scenarios, they face challenging problems due to fluctuations in the...
Optical systems are at the forefront of modern technologies, from telecommunications to quantum computing, offering unparalleled speed and efficiency in data processing and transmission. To develop and optimize these systems, engineers and scientists rely on tools like optical emulators. These tools play a critical role in modeling, testing, and refining optical networks, devices, and...
This talk concerns research of optical nanoscale materials which are synthesized/manufactured by our research team in Kyiv, and are being researched in Ukraine and beyond. The history of these studies goes back 11 years, and it was preceded by the study of the inorganic molecular anions (MA) like XOnm- (X = S, Se, Te, Cr, V, Mo, etc) in frozen aqueous solutions. Then, there were studies of...
The optical properties of glass-ceramic nanocomposite materials “oxide-glass matrix @ oxide-crystalline micro/nanoparticles filler” are now the subject of intensive research. The unique physical properties of such composites are determined by interphases regions, which have atomic structure and chemical composition intermediate between the crystalline and glass components. The atomic structure...
Elaboration of effective red phosphor for lighting applications remains one of the main directions in material science nowadays. Such phosphor should absorb part of ultraviolet or blue emission of the base chip and transform obtained energy into red light. Oxide compounds doped with rare-earth ions, namely Eu3+ ions, are among the candidates for such phosphors. It was found recently...
The global problem associated with the growth of terrorism has significantly worsened in the conditions of war in Ukraine due to the large-scale contamination of soil and water resources with explosives and explosion products. This makes the development of a sensitive, fast, cheap, portable and mass-producible sensor for the detection of explosives an urgent issue.
A number of attempts have...
Bismuth -containing phosphors contain multiple tetrahedral anions currently provide novel phosphors generation with improved functionality emerges, posing new challenges and opportunities in material science. The application of monovalent substitution by other rare-earth metals has been the focus of recent intense investigations because of the possible charge transfer processes, which brings...
This work investigates the use of texture analysis to establish a quantitative relationship between laser spot properties and the microrelief parameters of metal surfaces.Surface microreliefs, consisting of microscopic irregularities, play a crucial role in determining material properties. Analysis of these irregularities is crucial in materials science for predicting behavior, developing...
The paper is devoted to the development and research of hardware-software complex, computing methods and software for detecting missiles and UAVs using optical systems mounted on stationary platforms and support-rotating devices. The computational methods and software developed are designed to address the detection and tracking of target movement (trajectories) through optical systems, with an...
A terahertz (THz) range of an electromagnetic spectrum is considered to be used for the 6G wireless network. The important task of such networks is to design a collimated beam to increase the working distance between a source and a THz detector. One of the methods for rapid and targeted data transfer is applied directional beamforming technologies using interference of several antennas. Here...
Atomic-level engineering enables the creation of hybrid structures that enhance light-matter interactions and advance next-generation optical devices. Two-dimensional (2D) materials are important in nanophotonics due to their unique properties.
In this study, the authors introduce a hybrid vision transformer model, termed 2D-HVT, specifically designed for identifying and analyzing 2D...
Microfluidic devices have attracted significant attention in various scientific and industrial applications due to their precise control over small amounts of fluids. This study employs Computational Fluid Dynamics (CFD) to investigate and evaluate the mixing efficiency within a three-dimensional (3D) Y-shaped serpentine microfluidic device. The device is designed to mix two different fluids,...
Different types of nanoparticles are widely used because they have unique properties which make them suitable for the diagnostics and therapy (theranostics). They can improve detection selectivity and sensitivity, as imaging agents, delivery systems for encapsulated drugs, proteins and nucleic acids. Nanoparticles show high loading capacity, stability, high drug bioavailability and...
Fluorescence imaging is a perspective noninvasive optical technique to visualize emitting molecules and nanomaterials in biological objects. The limitation of this method is a depth of imaging due to a strong attenuation of light by the tissue, however, the use of near-infrared (NIR) irradiation allows for the visualization of objects under the tissue surface for millimeters. The tissue...
The Optical Kerr Effect (OKE) is a non-linear optical phenomenon in which an intense electric field induces a birefringence in the sample causing changes to the non-linear index (n2). The OKE is attributed to the distortion of the bound and free electrons and the disturbance of the molecular motions in a material.
Our work proposes the OKE as a potentially new method to differentiate differet...
Epitaxial growth of GaN and InGaN heterostructures is very promising for biosensor applications due to their excellent chemical stability, biocompatibility with low toxicity to living cells, and high carrier mobility [1]. Compared to InN thin films, InGaN quantum dot (QD)-based biosensors demonstrate a twofold increase in sensitivity and a fivefold faster response. While significant progress...
We investigate the interplay between self-focusing and higher harmonic generation (HHG) in a pre-formed, collisionless parabolic plasma channel. A $ q $-Gaussian laser beam, with its non-uniform intensity profile, induces a ponderomotive force that reshapes the plasma density distribution. This density gradient drives a plasma wave, which interacts with the laser to generate HHG. Using moment...
This theoretical study examines the interaction between Bessel-Gauss laser beams and ion acoustic waves (IAWs) in a plasma with a gradually increasing density profile. The focus is on how the laser beams self-focusing affects the power of the generated IAWs. As the laser propagates through the plasma, it excites an IAW at its characteristic frequency. Nonlinear coupling between the IAW and the...
The spatial distribution of number density of copper atoms in the plasma of electric arc discharge with copper vapour admixtures is determined by method of linear laser absorption spectroscopy. For this purpose, the discharge gap is illuminated by radiation of laser on the copper vapours. The absorption coefficient and, therefore, number density of absorbing species is determined from the...
Germanium optical elements are widely used as passive components (lenses, prisms, windows, protective screens) of the great majority of infrared devices. During operation, especially under extreme conditions, such elements frequently suffer mechanical damage or lose transparency resulting from the degradation of anti-reflective coatings.
The report presents the results of...
Materials based on double molybdates have a promising application in the field of optoelectronic devices[1] due to their physical and chemical properties, and they also exhibit the phenomenon of upconversion, which is widely used in diagnostics, therapy, sensors, solar cells, photocalysis, bio-imaging[2].
The main goal is to obtain pure NaBi(MoO4)2 and NaBi0.5Eu0.5(MoO4)2 with tetragonal...
Among the promising and innovative technologies of today, nanoelectromechanical systems, nanoelectronics, and its subdivision - spintronics, occupy a leading place. At the same time, one-dimensional structures - nanocontacts and nanowires - are of particular interest, based on which it is possible to form highly efficient nanocircuits with small dimensions and low power consumption. However,...
Infrared absorption spectra of free molecules (CH3)2CO/HCl and (CH3)2CO•••HCl complex are recorded in the 4000-400 cm−1 region with a Bruker IFS-125 Fourier spectrometer in gas state and with Kr, Xe solutions at different temperatures. In the free acetone and its complex with HCl, the spectral characteristics of the fundamental ranges Q(C=O),
, Q-(C-C), and νHCl are measured. Particular...
Glasses based on borophosphate with the formula (45-0.5x)P2O5-xB2O3-10,0MoO3-(45-0.5x)Na2O where 𝑥 = 20,0-60,0 have been manufactured using the melt-quenching methodology. Molybdenum oxide alone does not rank among glass-forming oxides, but it is able to enter the glass structure in the form of MoO4 tetrahedra or MoO6 octahedra with some glass-forming oxides, like P2O5. The regularities of...
Quantum chemical calculations of the structure and IR spectra of ibuprofen molecule were performed using various methods (HF, DFT, MP2). Several different conformers of ibuprofen were considered. The calculation results were compared with the experimentally registered spectra of ibuprofen. It is shown that MP2 method is the most appropriate for the description of the experimentally registered...
The analyzer-based imaging (ABI) is one of the most sensitive phase-contrast methods for weakly absorbing objects with low background due to high angular selectivity of analyzer crystal to scattered radiation. The most of the common approaches of ABI modelling are based on the approximation of geometrical optics for scattering in the non-crystalline sample and even in the analyzer crystal. At...
Optical properties of various transition-metal ions doped glasses have been under investigation in recent years in view of their technological applications, especially in lasers, phosphors, solar energy converters, plasma display panels and in a number of electronic devices. Molybdenum-containing glasses possess a variety of specific features, which arouse interest in view of their...
Microwave Kinetic Inductance Detectors (MKID) are widely used for detecting low-energy photons due to their high sensitivity and ease of multiplexing, with applications in astronomy and spectroscopy. This work investigates using Hilbert fractal planar resonators as a substitute for conventional straight or meander resonators in MKID. The study addresses challenges in miniaturizing resonators...
Multilayer ceramics have the potential to replace monolithic ceramics due to their improved mechanical properties, including increased hardness, durability, and fracture toughness. The diverse loading conditions faced by structural materials require the development of customized layered structures for specific applications. A key advantage of layered ceramic composites is their ability to...
Three-dimensional hybrid perovskites containing the aziridinium cation (AzrH)BX3 (where AzrH = aziridinium, B is Pb2+ or Sn2+ and X = Cl–, Br– or I–) exhibit semiconductive properties, making them suitable candidates for photovoltaic applications. Small changes in the composition of perovskites are shown to have a defining impact on optoelectronic properties of the reported materials. This...
Zinc oxide (ZnO) is one of the best photoactive wide-gap metal-oxide semiconductor materials, whose optoelectronic properties are of great interest for nanophotonics [1,2]. In particular, photoexcited ZnO exhibits strong excitonic UV photoluminescence (PL) at room temperature (RT). But despite all advances in ZnO nanophysics, some features of RT excitonic PL of ZnO nanoparticles (NP) are not...
Theoretical modeling of electronic structures of heterostructure composites is a powerful tool for developing novel optical materials. This work presents the results of calculations of the excited electronic states and optical spectra of MoO₄ groups and Bi ions, considered potential luminescence centers in the glass-ceramic composite "KBi(MoO₄)₂ crystal@phosphate-molybdate glass of...
Infrared spectra (4000-400 cm-1) of free molecules CX3Y (X=H, D, Y=F, Cl, Br), HCl, and CX3Y•••HCl mixtures in liquefied argon (90, 100-120 K) are recorded. The intermolecular interactions of the CX3Y•••HCl complexes are studied using the DFT method based on the B3LYP/6–311++G(d,p) basis set. The effect of deuterium (D), an isotope of the hydrogen atom (H), on the vibrational spectra of...
Polyvinylidene fluoride (PVDF) is an organic polymer that exhibits significant potential and commercial appeal for modern applications in nanotechnology, microelectronics, and biomedicine. A real PVDF polymer is almost always a mixture of several polymorphic phases that are difficult to separate. Determining the phase composition of PVDF mixtures is a critical technological task. This report...
The development of photovoltaic technology addresses the challenges posed by the energy crisis. A current priority in this field is to reduce the cost of solar cell (SC) production while achieving properties not typically found in crystalline silicon photovoltaic converters. Consequently, significant attention has shifted toward thin-film, organic, perovskite, and quantum dot solar cells....
Nonlinear Spatial Frequency Chirping Of Quadruple Gaussian Laser Beams Interacting with Narrowband Gap Semiconductors: Effect of Self Focusing
Nishu Malik and Naveen Gupta
Lovely Professional University, Phagwara
naveens222@rediffmail.com
nishumalik1230@gmail.com
Abstract
This paper investigates the nonlinear spatial frequency chirping (NSFC) of quadruple Gaussian (QG) laser...
Recently, increasing attention has been tuned to luminescence behaviour related to structure specialty of phosphor materials because microstructure of host material decides the fluorescence properties [1]. Phosphate is a good type of candidate for its reasonably large band gap, high thermal and chemical stability. The basic building block of phosphates is the PO4 tetrahedron and EuOx, which is...
This paper investigates the Gouy phase shift of Bessel-Gauss laser beams propagating through a plasma medium characterized by an axial temperature gradient. The interplay between the Bessel-Gauss beam profile and the self-focusing effect induced by the plasma is examined. The analytical expression for the Gouy phase shift is derived, incorporating the influence of both the beam's spatial...
Bismuth – containing oxide materials have been attraction much attention as phosphors for light emitting diodes and other devices. Among them these ones containing tungsten are rarely studied due to a low chemical activity of tungsten compounds and high velocity evaporation of WO3 under thermal treatment.
Currently, Bi2WO6 have been attracting significant attention as optical...
Beer is one of the most popular drinks in the world. It is produced both at large-scale factories and in small craft breweries. Both producers and distributors of beer require cost-effective and stable ways to control and verify the authenticity of the drink. Traditional methods of evaluating beer properties are often expensive and require significant resources [1]. Recently, the industry has...
We consider formation of EHL in a transition metal dichalcogenide monolayer in a stochastic approach. The theoretical foundations were formulated in [A.A. Chernyuk et al., Physics Letters A 384, 126185 (2020)] for studying exciton liquid formation in semi-conductor quantum wells. In this work, an exciton gas is created in dichalcogenide plane by pumping. The exciton flux through the island...
This study focuses on the synthesis of CdxTeyOz films using the SILAR (Successive Ionic Layer Adsorption and Reaction) method, a cost-effective chemical deposition technique that enables precise control of nanocomposite structures. By investigating two batches of films with varying treatment cycles (five and ten), the research highlights the relationship between synthesis conditions and the...
Homogeneous glasses and class-ceramics can be produced by molten glass and converting it into a fine-grained ceramic by an appropriate heat treatment. Generally, wide range of glass-ceramic properties can be modified in a predictable way by changing the composition with a suitable heat treatment. The final crystalline phases depend on the composition of the glass and the heating methods. Thus,...
This research aims to investigate noncovalent interactions in various thiophene-2-carboxylic acid (TCA) solutions through experiments and simulations. Raman and infrared (IR) spectroscopy were utilized to analyse the vibrational characteristics of TCA in various solvent solutions. Experimental data analyzed using computing approaches include highest occupied molecular orbital (HOMO) and lowest...
In many small molecules the direction of the chemical bond, defined as the direction of the greatest change in the molecule’s energy, appears not to coincide with the segment connecting the nuclei in a molecule. This phenomenon, first described in [1], is referred to as chemical bond deviation and has been thoroughly examined using classical 3N matrix method, e.g. [2], and ab initio methods,...
Non-contact optical thermometry is based on temperature dependence of fluorescence intensity ratio (FIR) of two spectral lines. Recently, fluorescence of rear-earth ions incorporated in wide-gap materials has been widely used for accurate temperature sensing.
Eu-doped and Sm-doped AlN thin films prepared by radio frequency magnetron sputtering were studied in terms of their applicability as...
