bluuebunny/crossref_metadata_2025 huggingface dataset:
Analysis of period and visibility of dual phase grating interferometer
Authors: Yang Jun , Huang Jian-Heng , Lei Yao-Hu , Zheng Jing-Biao , Shan Yu-Zheng , Guo Da-Yu , Guo Jin-Chuan
Published: November 2021

Dual phase grating interferometer may simultaneously achieve large field of view and high x-ray dose efficiency. Here, we develop a simple theoretical method to better understand the imaging process of the dual phase grating interferometer. The derivation process of fringe period and the optimal visibility conditions of the dual phase grating interferometer are given in detail. Then, we theoretically prove that the fringe period and optimal visibility conditions of the dual phase grating interferometer include that of the Talbot interferometer. By comparing our experimental results with those of other researchers, we find that when the positions of phase gratings are far away from the positions where the fringe visibility is optimal, the fringe period of the dual π-phase grating interferometer is twice the theoretical results under the illumination of polychromatic x-ray. This conclusion may explain the contradictory research results of dual phase grating interferometer among different researchers.
Comparative study of high temperature anti-oxidation property of sputtering deposited stoichiometric and Si-rich SiC films
Authors: Wang Hang-Hang , Lu Wen-Qi , Zhang Jiao , Xu Jun
Published: November 2021

Stoichiometric and silicon-rich (Si-rich) SiC films were deposited by microwave electron cyclotron resonance (MW-ECR) plasma enhanced RF magnetron sputtering method. As-deposited films were oxidized at 800 °C, 900 °C, and 1000 °C in air for 60 min. The chemical composition and structure of the films were analyzed by x-ray photoelectron spectroscopy (XPS), Raman spectroscopy and Fourier transform infrared spectroscopy (FT-IR). The surface morphology of the films before and after the high temperature oxidation was measured by atomic force microscopy. The mechanical property of the films was measured by a nano-indenter. The anti-oxidation temperature of the Si-rich SiC film is 100 °C higher than that of the stoichiometric SiC film. The oxidation layer thickness of the Si-rich SiC film is thinner than that of the stoichiometric SiC film in depth direction. The large amount of extra silicon in the Si-rich SiC film plays an important role in the improvement of its high temperature anti-oxidation property.
Tunable electronic properties of GaS–SnS2 heterostructure by strain and electric field
Authors: Ren Da-Hua , Li Qiang , Qian Kai , Tan Xing-Yi
Published: November 2021

Vertically stacked heterostructures have received extensive attention because of their tunable electronic structures and outstanding optical properties. In this work, we study the structural, electronic, and optical properties of vertically stacked GaS–SnS2 heterostructure under the frame of density functional theory. We find that the stacked GaS–SnS2 heterostructure is a semiconductor with a suitable indirect band gap of 1.82 eV, exhibiting a type-II band alignment for easily separating the photo-generated carriers. The electronic properties of GaS–SnS2 heterostructure can be effectively tuned by an external strain and electric field. The optical absorption of GaS–SnS2 heterostructure is more enhanced than those of the GaS monolayer and SnS2 monolayer in the visible light region. Our results suggest that the GaS–SnS2 heterostructure is a promising candidate for the photocatalyst and photoelectronic devices in the visible light region.
Photometric and Spectroscopic Analysis of LBV Candidate J004341.84+411112.0 in M31
Authors: Sarkisyan A. , Sholukhova O. , Fabrika S. , Valeev A. , Valcheva A. , Nedialkov P. , Tatarnikov A.
Published: November 2021

We study Luminous Blue Variable (LBV) candidate J004341.84+411112.0 in the Andromeda galaxy. We present optical spectra of the object obtained with the 6 m telescope of BTA SAO RAS. The candidate shows typical LBV features in its spectra: broad and strong hydrogen lines and the He i lines with P Cygni profiles. Its remarkable spectral resemblance to the well known LBV P Cygni suggests a common nature of the objects and supports LBV classification of J004341.84+411112.0. We estimate the temperature, reddening, radius and luminosity of the star using its spectral energy distribution. Obtained bolometric luminosity of the candidate (M
bol = −10.41 ± 0.12 mag) is quite similar to those of known LBV stars in the Andromeda galaxy. We analyzed a ten year light curve of the object in R filter. The candidate demonstrates photometric variations of the order of 0.4 mag, with an overall brightness increasing trend ΔR > 0.1 mag. Therewith, the corresponding color variations of the object are fully consistent with LBV behavior when a star become cooler and brighter in the optical spectral range with a nearly constant bolometric luminosity. LBV-type variability of the object, similarity of its spectrum and estimated luminosity to those of known LBVs allow us to classify J004341.84+411112.0 as an LBV.
Effect of the lattice mismatch on the efficiency of the GaAs nanowire/Si substrate solar cell
Authors: Alekseev P A , Sharov V A , Borodin B R , Dunaevskiy M S , Reznik R R , Cirlin G E
Published: November 2021

The effect of the crystal lattice mismatch between single p-GaAs nanowire grown on p-Si substrate on the solar cell efficiency is studied. The study is performed by measuring the I-V curves under red (wavelength=650 nm) laser illumination. The measurement of the single nanowire was done by conductive atomic force microscopy (C-AFM). The measured curve was reproduced by numerical simulations accounting piezoresistance and piezoelectric effects. The analysis demonstrated the presence of the tensile (2%) zinc blend insert at the interface between nanowire and substrate induced by crystal lattices mismatch. Strained insert at the interface changes the polarity of the photogenerated current and increases the efficiency by 2 times.
Enhancement of second harmonic generation in a layered MoS2 nanoresonator
Authors: Antropov I.M. , Popkova A.A. , Tselikov G.I. , Volkov V.S. , Bessonov V.O. , Fedyanin A.A.
Published: November 2021

Molybdenum disulfide (MoS2) is a layered material with a high refractive index in the visible and infrared spectral range. In this work, we theoretically and experimentally demonstrate Mie-resonant MoS2 nanodisks. We show enhanced second harmonic generation from MoS2 nanodisk resonators due to the overlap of Mie-type resonances at the fundamental wavelength with the C-exciton resonance at the second-harmonic wavelength.
Polarization degeneracy of TE and TM eigenmodes for dielectric metasurface in the microwave
Authors: Asadulina Syuzanna , Bogdanov Andrey , Glybovski Stanislav , Yermakov Oleh
Published: November 2021

We analyze the TE-TM polarization degeneracy of the guided modes of a dielectric metasurface in the microwave frequency range. We find the optimum metasurface design and investigate the dependence of the degeneracy degree on the propagation direction. Finally, we simulate the possible microwave experiment demonstrating the extraction of isofrequency contours for this metasurface. The results obtained could be useful for flat photonic devices with the function of polarization control.
Large-scale ReRAM device based on HKUST-1 thin film
Authors: Bachinin Semyon V. , Rzhevskiy Sergey S. , Milichko Valentin A.
Published: November 2021

The humanity creates more and more information every day. This aspect collides on a big problem – storage and processing. We can separate this problem on two tasks – choose some technologies which can satisfy modern requirement and searching new perspective material suitable for creating data-storage device. Herein, we demonstrate a concept of solving this problem by matching ReRAM – technology and metal-organic frameworks. We have achieved significant results and created a large-scale device with remarkable characteristics on/off ration.
Fabrication of Au and Ag – Coated AFM Probes for Tip-Enhanced Raman Spectroscopy
Authors: Basalaeva L S , Kurus N N , Rodyakina E E , Anikin K V , Milekhin A G
Published: November 2021

In this work, approaches for fabrication metal coated probes for Tip Enhanced Raman Spectroscopy (TERS) are considered. It was proposed to use optical characterization of probes to achieve the effective TERS of semiconductor nanoobjects. The shape and size of the metal cluster at the tip apex determines the position of the localized surface plasmon resonance, the electromagnetic field enhancement and, thus, TERS performance. The possibility of optimizing the characteristics of the probes for TERS studies of nanoobjects has been investigated.
Altering the distribution of excited-state lifetimes in aminated GFP chromophores by Ag nanohole arrays
Authors: Aslopovsky VR , Shakhov AM , Astafiev AA , Bochenkov VE
Published: November 2021

Fluorescence of the modified GFP chromophore diethyl-ABDI-BF2 dispersed in PMMA matrix is studied on top of glass, continuous and perforated optically thin silver films. In polymer, the fluorescence decay kinetics becomes non-exponential and can be described by the distribution of rate constants. The results demonstrate shortening of the excited state lifetime in the presence of silver and broadening of the lifetime distribution caused by the nanoholes.
Mechanical scanning probe lithography of nanophotonic devices based on multilayer TMDCs
Authors: Borodin B R , Benimetskiy F A , Davydov V Yu , Eliseyev I A , Lepeshov S I , Bogdanov A A , Alekseev P A
Published: November 2021

In this work, we demonstrate the possibility of using mechanical Scanning probe lithography (m-SPL) for fabricating nanophotonic devices based on multilayered transition metal dichalcogenides (TMDCs). By m-SPM, we created a nanophotonic resonator from a 70-nm thick MoSe2 flake transferred on Si/Au substrate. The optical properties of the created structure were investigated by measuring microphotoluminescence. The resonator exhibits four resonance PL peaks shifted in the long-wavelength area from the flake PL peak. Thus, here we demonstrate that m-SPL is a high-precision lithography method suitable for creating nanophotonic devices based on multilayered TMDCs.
On the link between mean square-radii and high-order toroidal moments
Authors: Borovkov Dmitrii , Valero Adrià Canós
Published: November 2021

Multipole expansions of the source play an important role in a broad range of disciplines in modern physics, ranging from the description of exotic states of matter to the design of nanoantennas in photonics. Within the context of the latter, toroidal multipoles, a third group of multipoles complementing the well-known electric and magnetic ones, have been widely investigated since they lead to the formation of non-radiating sources. In the last years, however, the photonics community has brought to light the existence of a fourth type of multipoles that is commonly overlooked. Currently, different groups have provided different mathematical expressions to describe such sources, and they have been coined with different names; on the one hand mean-square radii, and on the other hand, as high order toroidal moments. Despite their clear physical similarity, a formal relation between the two has not yet been established. While explicit formulas for both types have been derived, they are not expressed in the same basis, and therefore it is not possible to draw a clear physical connection between them. In this contribution, we will bridge this gap and rigorously derive the connection between the two representations, taking as an example the cases of the nth order mean square radius of the electric dipole and the nth order electric toroidal dipole. Our results conclusively show that both types of representations are exactly equivalent up to a prefactor.
Directional luminescence of the diamond NV center via Bloch surface waves in one-dimensional photonic crystals
Authors: Bragina A A , Safronov K R , Bessonov V O , Fedyanin A A
Published: November 2021

In this work, we numerically study the luminescence of nanodiamonds with NV centres embedded in a polymer layer on the surface of one-dimensional photonic crystal. The interaction of NV center spontaneous emission with the Bloch surface wave (BSW) is demonstrated. The presence of a photonic crystal leads to a change in the angular distribution of the emitter radiation due to the coupling of luminescence to BSW. We show that the best coupling efficiency of 71% is observed when NV centres are located in the close proximity to the BSW field maximum.
Extracting Dielectric Permittivity with a Cross-Like Stripline
Authors: Burtsev Vladimir , Vosheva Tatyana , Filonov Dmitry
Published: November 2021

Parametric retrieval of electromagnetic properties is important for both new materials characterization and an accurate design of devices. While quite a few techniques have been developed over the years, precise mapping of high-permittivity samples remain challenging. Here we advance a so-called micro-strip technique, where transmission coefficients of a waveguide system with an analyte on top are used to extract electromagnetic parameters of the later. Our cross-like strip line configuration has a split ring resonator on one edge and an open circuit termination on another. This design allows performing a simultaneous test of cylindrical and rectangular samples. Our new post-processing scheme was tested on a water-filled container and showed 96.3% accuracy, assessed by comparing our results with tabulated data.
Exceptional points of all-dielectric nanoresonators
Authors: Valero Adrià Canós
Published: November 2021

In the recent years, all-dielectric nanophotonics has been showing promising potential for biotechnology, with important progress in the development of efficient all-optical, all-dielectric nanosensing devices overcoming the ohmic losses inherently present in their plasmonic counterparts. In the quest to achieve single molecule sensitivities, a judicious design of the optical response of the nanoantennas is required. Here, we approach this problem from the perspective of non-Hermitian physics and investigate the interaction of two finite nanorods supporting Mie resonances, with the aim of maximizing the frequency detuning induced by a perturbation of the structure. We develop a simple semi-analytical technique to efficiently investigate the coupled system, and we find that Coulomb interactions, together with mutual interference induced by breaking the dimer symmetry, can effectively bring the structure towards a non-Hermitian singularity, an exceptional point, that can potentially increase the sensitivity. The results of this work are expected to lead to novel developments in all-optical single molecule detection, and merge for the first time all-dielectric nanophotonics with exceptional point physics.
Optical Heating Controlled With a Thermoplasmonic Metasurface
Authors: Chernykh E A , Filippov A N , Alekseev A M , Makhiboroda M A , Kharintsev S S
Published: November 2021

We develop a photothermal technology to control optical heating of polymer and liquid crystal films through a refractory titanium nitride (TiN) metasurface. The metasurface represents an array of identical square-shaped TiN nanoantennas on a Si substrate. Upon CW laser illumination, a TiN nanoantenna experiences anomalous Joule heating at a plasmon resonance. A temperature rise provides a unique opportunity for locally probing phase transitions. In the case of heterogeneous PMMA thin films or polymeric blends, a controlled optical heating is needed to probe the glass transition temperature (Tg) of their constituents. Here, we model a controlled thermal response originating from the TiN nanoantenna under CW laser illumination by using FDTD/FEM methods.
Pump-probe spectroscopy in gold-garnet magnetoplasmonic metasurfaces
Authors: Dolgova T V , Kiryanov M A , Nurgalieva P K , Ostanin G S , Musorin A I , Uchida H , Inoue M , Fedyanin A A
Published: November 2021

Ultrafast modulation of optical response is realized in a multi-resonant magnetoplasmonic metasurface under resonant femtosecond pump. A saturation of resonant probe transient transmission is shown at dielectric quazi-waveguide mode.
Functional Photonic Elements Based on Liquid Crystal Metasurfaces
Authors: Gorkunov Maxim V. , Kasyanova Irina V. , Artemov Vladimir V. , Geivandov Artur R. , Simdyankin Ivan V. , Mamonova Alena V. , Ezhov Alexander A. , Palto Serguei P.
Published: November 2021

We study versatile soft-matter metasurfaces based on self-assembling of nematic liquid crystal on polymer alignment layers processed with a focused ion beam. Digital control of the beam path allows imprinting patterns that induce different complex distributions of the refractive index within several micrometer thick liquid crystal layers. We optimize them to implement various optical functionalities, such as broadband anomalous refraction, wide-aperture focusing, and beam splitting in tens of channels.
Structure and properties of the low-energy deposited TiO2 thin films: results of the molecular dynamics simulation
Authors: Grigoriev F.V. , Sulimov V.B. , Tikhonravov A.V.
Published: November 2021

The classical molecular dynamics simulation of the low-energy glancing angle deposition of titanium dioxide films is performed. The deposition angle varies from 60° to 80°. It is found that the film structure consists of parallel slanted columns which lead to the anisotropy of films properties. The difference between the main components of the refractive index tensor is about 0.14, which is close to the values obtained for high-energy titanium dioxide films and larger than 0.03 obtained earlier for silicon dioxide films.
Realizing Spin-Conserved and Spin-Encrypted Hologram using Multipolar-modulated Meta-platform
Authors: Khaliq Hafiz Saad , Kim Inki , Riaz Kashif , Naeem Taimoor , Zubair Muhammad , Rho Junsuk , Mehmood Muhammad Qasim
Published: November 2021

The chiro-optical effects complemented with polarization conservation and wavefront shaping finds potential applications in advanced imaging, sorting and detection of enantiomers and quantum optics. Here, a unique design strategy proposed to manifest enormous chiro-optical effects using achiral structures (instead of conventional chiral antennas). The basic building block of the meta-platform contains a pair of achiral structures. The underlying mechanism behind the giant chiro-optical effects is explained by numerically calculating the multipolar resonances of scattering power. The designed diatomic meta-platform achieves absolute control over spin and wavefront of incident light to demonstrate the polarization-conserved and -encrypted meta-holograms.
Electron-energy-loss spectroscopy and cathodoluminescence for particles inside substrate
Authors: Kichigin Alexander A , Yurkin Maxim A
Published: November 2021

To simulate the interaction of a nanoparticle with an electron beam, we previously developed a theoretical description for the general case of a particle fully embedded in an infinite arbitrary host medium. The theory is based on the volume-integral variant of frequency-domain Maxwell’s equations and, therefore, is naturally applicable in the discrete-dipole approximation. The fully-embedded approximation allows fast numerical simulations of the experiments for particles inside a substrate since the host medium discretization is not needed. In this work, we study how applicable the fully-embedded approach is for realistic scenarios with relatively thin substrates. In particular, we performed test simulations for a silver sphere both inside an infinite host medium and inside a finite box or sphere. For the host medium, we considered two non-absorbing cases (the denser one causes Cherenkov radiation), as well as an absorbing case. The peak positions in the obtained spectra approximately agree between substrates a few times thicker than the sphere and the infinite one. However, a much thicker substrate (of the order of μm) would be required to have a qualitative agreement for absolute peak amplitudes. The developed algorithm is implemented in the open-source code ADDA, allowing one to rigorously and efficiently simulate electron-energy-loss spectroscopy and cathodoluminescence by particles of arbitrary shape and internal structure embedded into any homogeneous host medium.
Investigation of the Phonon Spectra in CdSe/CdS Nanoplatelets by Raman Spectroscopy
Authors: Kurus N.N. , Milekhin A.G. , Vasiliev R.B. , Saidzhonov B.M. , Anikin K.V. , Sklyar R.I. , Batsanov S.A. , Gutakoskii A.K. , Latyshev A.V. , Zahn D.R.T.
Published: November 2021

We report the phonon spectra of core/shell CdSe/CdS nanoplatelets with different shell thicknesses studied using Raman scattering. The nanoplatelets are rectangular colloidal nanocrystals, with thicknesses of core and shell layers of a few nanometers. The Raman spectra show features corresponding to the dominating longitudinal optical (LO) and surface optical (SO) phonon modes of the CdSe core in CdS shell located in the frequency regions of 200-210 and 250-290 cm-1, respectively. As the shell thickness increases, the phonon modes reveal a frequency shift and a change in intensity. The frequency shift associated with a change in the stress state in the core and shell, as well as with confinement effects is discussed. The phonon mode intensities are determined by the thickness of the shell and the proximity to resonant Raman scattering conditions.
Planar Modulated Reactance Surfaces for Endfire Antenna Applications
Authors: Kwon Do-Hoon
Published: November 2021

Modulated reactance synthesis for planar impenetrable electromagnetic surfaces for endfire radiation characteristics is presented. It is based on aperture field synthesis over the entire spectral range, where the desired radiation pattern is prescribed by a traveling-wave current over the aperture. Carefully constructed auxiliary waves in the evanescent spectrum are added and the total aperture fields are optimized such that the entire aperture surface becomes pointwise reactive. The optimized aperture fields define the modulated surface reactance that realizes the desired pattern when excited by a feed surface wave. The reactance distribution may be realized as modulated metasurfaces.
Long-Term Stable Structures Formed by Ion-Beam Modification of Silver Film for SERS Applications
Authors: Novikov S. M. , Streletskiy O. A. , Doroshina N.V. , Yakubovsky D. I. , Mironov M. S. , Sychev V. V. , Voronov A. A. , Arsenin A. V. , Volkov V. S.
Published: November 2021

Ensembles of silver nanoparticles (NPs) with size ~45 nm formed from the silver film using an ion beam modification are studied. The optical spectroscopy demonstrated that the fabricated ensembles of silver NPs keep stable their plasmonic properties in an ambient atmosphere for at least 39 days due to their monocrystalline nature. We use the scanning Raman microscope to map the SERS from Crystal Violet homogeneously adsorbed on these ensembles. It was found that the manufactured ensembles have a strong amplification factor, and this factor is preserved for these ensembles even after more than one month of storage in the surrounding atmosphere. Hereby, by ion beam modification of silver film, it is possible to fabricate the NPs with stable plasmonic properties and form nanostructured surfaces to be applied in sensor technologies and SERS.
Purcell enhancement of fluorescence from silicon-vacancy color centers in Mie-resonant luminescent diamond particles
Authors: Obydennov Dmitry V , Elyas Ekaterina I , Shilkin Daniil A , Yaroshenko Vitaly V , Zuev Dmitriy A , Lyubin Evgeny V , Ekimov Evgeny A , Kudryavtsev Oleg S , Vlasov Igor I , Fedyanin Andrey A
Published: November 2021

Over the past two decades, nanosized diamond particles with various luminescent defects have found numerous applications in many areas from quantum technologies to medical science. The size and shape of diamond particles can affect drastically the luminescence of embedded color centers. Here we study diamond particles of 250–450 nm in size containing silicon-vacancy (SiV) centers. Using dark-field scattering spectroscopy, we found that fundamental Mie resonances are excited in the spectral range of interest. We then measured the fluorescence saturation curves under continuous excitation to estimate the effects of the excitation and Purcell factor enhancement on the luminescent properties of the studied particles. The results show that the saturation excitation intensity differs by several times for particles of different sizes which is well explained by the numerical model that takes into account both the Parcell factor enhancement and resonant excitation.
DFT analysis of crystal polarity on graphene surface
Authors: Pavlov Alexander , Mozharov Alexey , Berdnikov Yury , Barbier Camille , Harmand Jean-Christophe , Tchernycheva Maria , Polozkov Roman , Mukhin Ivan
Published: November 2021

We report an ab-initio study of the preferred polarity for wurtzite GaN nanostructures on virtual graphene substrates. By means of the density functional theory analysis we show that N-polar nanostructures on graphene are energetically favorable in comparison to Ga-polar. These finding are in agreement with experimentally observed N-polarity of wurtzite GaN nanowires grown on graphene substrate. We believe that the revealed polarity preference is of importance for piezoelectric and optoelectronic device design.
Ablation-Free Laser Printing of Structural Colors in Reflection at 25,000 DPI
Authors: Pavlov D , Lapidas V , Zhizhchenko A , Storozhenko D , Kuchmizhak A
Published: November 2021

Using direct femtosecond laser patterning of metal-insulator-metal (MIM) sandwich designed to support Fabry-Perot mode in the visible spectral range we demonstrate new practically relevant strategy for high-resolution color printing. Irradiation of the MIM sandwich by tightly focused laser pulses allows to produce unique 3D surface nanostructures – hollow nanobumps and nanojets - locally modulating surface reflectivity. Laser processing parameters control the 3D shape of such nanostructures allowing to gradually tune the reflected color from reddish brown to pure green. Up-scalable ablation-free laser fabrication method paves the way towards various applications ranging from large-scale structural color printing to optical sensors and security labeling at a lateral resolution of 25,000 dots per inch.
Semitransparent visualizers of infrared lasers based on perovskite quantum dots
Authors: Polushkin A S , Zelenkov L E , Khmelevskaia D , Markina D I , Rogach A L , Makarov S V
Published: November 2021

These days halide perovskite is a very popular material to be applied both in photovoltaics and photonics due to its unique properties and low-cost methods of fabrication. High photoluminescence quantum yield and good nonlinear coefficients of perovskite material allow achieving multiphoton absorption in perovskite. Encapsulation of perovskite quantum dots in polymer matrix enables to prevent interaction with the environment and increase the material lifetime. In this paper, we present a semitransparent visualizer of infrared lasers working on two-photon absorption in halide perovskite nanocrystals encapsulated in the polymer matrix.
Temporal transition in parallel-plate waveguides: analysis of scattering and propagation at the temporal interface
Authors: Stefanini L. , Ramaccia D. , Toscano A. , Bilotti F.
Published: November 2021

In this contribution, we present the analysis and numerical verification of the scattering phenomenon from a temporal interface in a parallel-plate waveguide realized by suddenly modifying the dimensions of the waveguide while the wave is propagating. As it is well known in guided wave theory, at the interface between two different waveguides there exists a change of the effective refractive index and wave impedance perceived by the propagating wave within the device, which inevitably scatters at the interface into a reflected and refracted wave. In analogous way, by suddenly changing the effective material properties within the whole waveguide, it is possible to realize the so-called temporal interface, as well. Here, we theoretically and numerically investigate on the scattering from a waveguide temporal interface induced by the abrupt change of the waveguide dimension, which in turn realize a change of the effective material properties perceived by the wave.
Highly Chiral Exceptional Point in Perturbed Coupled Resonators
Authors: Ramezanpour S. , Ra’di Y. , Alù A. , Bogdanov A.
Published: November 2021

Exceptional point (EP) is a non-Hermitian spectral degeneracy that has application in ultrasensitive sensors and laser mode selectivity. By employing strong chirality in an optical system, the direction of light propagation can be controlled and subwavelength particles can be detected. Here, we show that EP with high chirality can appear in the coupled resonators perturbed by a scatterer, in which both the distance and position of the scatterer can be tuned. We achieve strong chiral EP in two different distances between the resonators, with chirality around 0.99 in both cases.
Retrieving the refractive index of a sphere from the phase spectrum of its light-scattering profile
Authors: Romanov A V , Yurkin M A
Published: November 2021

We studied the Fourier spectrum of the light-scattering profiles of single particles in the Rayleigh-Gans-Debye (RGD) and Wentzel–Kramers–Brillouin (WKB) approximations. In the case of a homogeneous sphere, we found the relationship between the key parameters of the spectrum (including its phase) and the sphere characteristics – both analytically and numerically in the framework of the approximations and the rigorous Lorentz–Mie theory, respectively. Based on these results, we have improved the existing spectral characterization method for spheres extending the applicability range to particles with a higher refractive index.
Nonlinear TMOKE enhancement in 1D Au/Py magnetoplasmonic crystals
Authors: Romashkina A. M. , Novikov V.B. , Murzina T.V.
Published: November 2021

Resonant optical properties of the magnetoplasmonic crystals, which support propagation of surface plasmon polaritons (SPPs) accompanied by magnetooptical effects, have found success in magnetic field driven control of optical radiation. In this work we investigate the resonant magnetooptical effects in the second harmonic generation in the magnetoplasmonic crystal formed by gold/pemalloy bifilm covering dielectric grating. Strong transverse magnetooptical Kerr with the contrast up to 30% is revealed in the spectral vicinity of the SPP excitation.
Tetra-axial metamaterial
Authors: Sakhno D. , Koreshin E. , Belov P.
Published: November 2021

In this work we theoretically and numerically demonstrate that triple non-connected wire medium has four optical axes. The axes coinside with diagonals of the unit cell.
Supercattering Channels of Nonspherical structurers
Authors: Shamkhi H.K. , Canós Valero A.
Published: November 2021

A superscattering structure is an efficient energy-mapping device that of particular importance for various electromagnetic experiment methods, with potential sensing and energy harvesting applications. We study in this work the scattering cross-section of outgoing channels in the irreducible and singular basis for an arbitrary shape scatterer. The superscattering status is shown to occur within a single outgoing channel of an optimized cluster of cylinders, a forbidden mechanism in spherically symmetric Mie resonators.
A Mode Decoupling Method for Circular Patch Antennas
Authors: Siganov M. , Glybovski S. , Tatarnikov D.
Published: November 2021

In this contribution, we investigate the effect of mode decoupling for dual-feed circular patch antennas. We consider an antenna comprising a circular disc patch placed inside an annular-ring patch. Both patches are resonant radiators, which can be fed by two different vertical posts. Due to the field interaction of the patches, the feeds experience parasitic cross-talk limiting the receive diversity performance of the system. Here, we demonstrate the possibility to suppress the cross-talk at the operational frequency by including a capacitive decoupling element into the circular patch. The physical mechanism of the method consists in the excitation of two different eigenmodes (TM01 and TM11) in a certain combination canceling the mutual coupling. The presented decoupling method can be used for patches operating either at the same frequency or at two different frequencies. In the proposed dual-feed antenna it is possible to achieve an isolation level of better than -45 dB. In contrast to the method of decoupling and matching network used for the same type of antennas, one does not need couplers to feed the patches, which reduces losses.
UV/Ozone Treatment and Open-Air Copper Plasmonics
Authors: Solovey V. R. , Yakubovsky D. I. , Ermolayev G. A. , Lebedinskij Y. Y. , Markeev A. M. , Voronov A. A. , Zamboni F. , Popok V. N. , Arsenin A. V. , Volkov V. S. , Novikov S. M.
Published: November 2021

Thin copper films with thickness ∼28 nm deposited on SiO2 substrate with the vacuum electron beam evaporation method and treated by UV-ozone are studied. It was found that a UV-ozone treatment of the copper film causes rapid formation of the thin ∼3-4 nm oxide film. XPS analysis showed that CuO oxide predominates in this film. The formed oxide film effectively protects the copper against the following oxidation. The presented method of UV-ozone treatment is a simpler and cheaper approach compared to many other ways to form protective coatings of copper to preserve its functional properties. This method can be useful in nanoelectronic, nanooptical, and biosensors applications.
Omnidirectional Photonic Bandgap in Two-dimensional Photonic Quasicrystal Made of Near-Transparent Dielectric Material
Authors: Yafasov Ruslan , Sidorenko Mikhail , Rybin Mikhail , Petrov Alexander , Sayanskiy Andrey
Published: November 2021

Complete bandgap for all-dielectric photonic crystals in the microwave region can be obtained only by using high-contrast materials. This requires the usage of dielectric materials with high relative permittivity coefficient. In this paper, we study, both numerically and experimentally, a two-dimensional all-dielectric photonic quasicrystal made of polyurethane foam, which is considered in all microwave applications as a transparent material. The quasicrystal structure having an omnidirectional two-dimensional bandgap is mathematically generated by the direct inscription of Bragg’s peaks of the structure in the reciprocal space. The sample of the quasicrystal was manufactured on CNC (computer numerical controlled) milling machine out of foam with very low dielectric permittivity of 1.254. The numerical simulations and the experimental study are in good agreement with the theoretical model.
Numerical Study of Non-Radiating Near-Field Wireless Power Transfer System
Authors: Zanganeh E , Song M , Korobkov M , Evlyukhin A , Miroshnichenko A , Kapitanova P
Published: November 2021

The main challenge in near-field wireless power transfer systems is the increase of power transfer efficiency. It can be achieved by reducing ohmic or radiation losses of the resonators included in the system. In this paper, we propose and investigate numerically a non-radiating near-field wireless power transfer system based on transmitter and receiver implemented as dielectric disk resonators. The transmitter and receiver geometrical parameters are numerically optimized to operate at the frequency of non-radiating state of high refractive index dielectric resonators instead of magnetic dipole mode. Under the non-radiating state, we determine the frequency with almost zero radiation to the far-field. We numerically study the wireless power transfer efficiency as a function of operation distance between the transmitter and receiver and demonstrate that the higher efficiency compared to magnetic dipole mode can be achieved at non-radiating state for a fixed distance due to suppression of the radiation loss.
On the solvability of a boundary value problem for a quasilinear equation of mixed type with two degeneration lines
Authors: Rasulov Xaydar R.
Published: November 2021

The article investigates the existence of a generalized solution to one boundary value problem for an equation of mixed type with two lines of degeneration in the weighted space of S.L. Sobolev. In proving the existence of a generalized solution, the spaces of functions U(Ω) and V (Ω) are introduced, the spaces H1(Ω) and

H
1
*

(Ω) are defined as the completion of these spaces of functions, respectively, with respect to the weighted norms, including the functions K(y) and N(x). Using an auxiliary boundary value problem for a first order partial differential equation, Kondrashov’s theorem on the compactness of the embedding of

W
2
1

(Ω) in L2(Ω) and Vishik’s lemma, the existence of a solution to the boundary value problem is proved.
Program for Solving Assignment Problems and Its Application in Lecturer Resources Allocation
Authors: Wattanasiripong N , Sangwaranatee N W
Published: November 2021

This paper proposes program for solving assignment problems by Hungarian method. Assignment problem is one of the most famous problems in linear programming and in combinatorial optimization. It can be solved by using an efficient method which is called Hangarian method. In this problem, commonly, there are a number of agents and a number of tasks. Any agent can be assigned to perform any task. The objective of this problem is to decide the right agent to perform the right task and also the total cost of the assignment is minimized. The manual calculation is time-consuming and prone to mistake. Therefore, this program can help to find the optimal solution with less time. In this approach, computer programming is used as an implementation tool to get the accurate solutions. The program can also be applied with the lecturer allocation for each subject to minimize lecturer’s preparation time and to match the lecturer per individual expertise.
Some properties of germanene when adsorption of NH3 in the external field
Authors: Ngoc Hoang Van
Published: November 2021

This work studies on germanene when adsorbing NH3 gas, the system is placed in an 0 external electric field of 0.3 V / AÅ. By using the density functional theory (DFT) and VASP software, the properties of the energy band structure, the density of the state, and the charge displacement have been studied. There are four locations in which NH3 doped research is hollow, bridge, valley, and top. At the bridge position for the minimum adsorption energy, this indicates that the bridge position is the most optimal position when doped with NH3. The state density energy region structure, the charge displacement will be studied for the most optimal position. Placing the system in an external electric field will change the energy band structure as well as other properties of the NH3 doped germanene. This study will be useful for all steps of research in sensor or biomedical.
Structural, morphological and thermal analysis of pure and doped (Ho/Nd)-BFO multiferroics
Authors: Gokul C M , Mohan Aiswarya , Nair Soumya G , Dhanya S R , Satapathy Jyotirmayee
Published: November 2021

Pure BiFeO3(BFO) and 20% doped BFO with Holmium (Ho) and Neodymium (Nd) separately (Ho-BFO and Nd-BFO) samples are synthesized using solid state reaction method. Structural characterization is carried out using XRD and FTIR analysis. Further morphological study is performed to assist the structural analysis. In addition to these, thermal analyses such as tg-DTA comparisons are also presented here. These studies provide the understanding of impact of doping in modifying structure and related inherent properties of BFO multiferroics which are normally associated with their tuned electric and magnetic properties.
A comparative study of the dosimetric impact on IMRT planning with VMAT plans using a varying number of arcs in prostate cancer
Authors: Kumar D , Pradhan A , Singh L M
Published: November 2021

A study has been carried out to explore the impact by varying the number of arcs and beam arrangement on dose distributions. For this volumetric modulated arc therapy and 7-field, intensity-modulated radiation therapy plans have use for prostate cancer cases. The eclipse treatment planning system version 13.6 (Varian California, USA) was used to assess dosimetry data for 20 patients. All patients received intensity-modulated radiation therapy and volumetric modulated arc therapy plans with a varying number of arcs. 6MV X-Ray photon beam energy uses for each patient. Statistical plan assessments have been carried out for various dosimetric parameters to evaluate execution efficiency. There were no statistically significant changes (p>0.05) observed in D98% dose coverage while D2%, conformity index, homogeneity index, monitor unit, and treatment delivery time were showing statistically significant changes (p<0.05). In contrast to six arc volumetric modulated arc therapy and 7 field-intensity-modulated radiation therapy plans, Single arc volumetric modulated arc therapy plans showed 23.28 % and 25.96 % less monitor unit, 97.52 % and 137.53 % less treatment delivery time. It concluded that using a higher number of arcs in volumetric modulated arc therapy plans for prostate cancer improves plan efficiency. The four arc volumetric modulated arc therapy plans appeared to provide a reasonable trade-off between enhanced treatment delivery time and high treatment plan quality.
DFT analysis of Thymine adsorption on Ti doped graphene for biosensor applications
Authors: Qasem Jawaher , Pardeshi Prashant , Ingle Avinash , Karde Ravindra , Ali Shamsan , Lone Baliram
Published: November 2021

Density functional theory quantum chemical calculations have been performed to investigate the adsorption of thymine on pristine graphene (Gr) and Titanium doped graphene (GrTi) in order to explore the potential of doped graphene as adsorbent for biomolecule DNA nucleobase thymine. The various parameters including adsorption energy, mode of charge transfer, dipole moment, HOMO-LUMO gap and DOS confirms the Ti doped graphene can be good candidate as adsorbent for thymine in terms of biosensor applications.
First-principles calculations of electronic and optical properties in the bulk and on the (001) surface of CsPbCl3
Authors: Soni K , Jain V , Lakshmi N
Published: November 2021

We perform density functional theory using first-principles calculations in order to investigate the band structure, density of states, the real and imaginary part of dielectric function, refractive index and optical absorption of CsPbCl3 in the bulk and (001) surface structure. Energy bands exhibits wide and direct bandgap. When CsPbCl3 is extended to (001) surface a decrease of band gap is observed with increasing thickness. The optical constants observed exhibits optimal properties in the ultraviolet and visible range indicating its usefulness in photonic, optoelectronic, photovoltaic and optomagnetic devices.
The existence of eigenvalues of Schrödinger operator on a lattice in the gap of the essential spectrum
Authors: Abdullaev J.I. , Khalkhuzhaev A.M.
Published: November 2021

We consider a three-particle discrete Schrödinger operator Hμγ
(K), K 2 T3 associated to a system of three particles (two fermions and one different particle) interacting through zero range pairwise potential μ > 0 on the three-dimensional lattice Z
3. It is proved that the operator Hμγ
(K), ||K|| < δ, for γ > γ0 has at least two eigenvalues in the gap of the essential spectrum for sufficiently large μ > 0.
Recent Advances in Tin-based Hybrid Organic-Inorganic PSCs: Additives for Improved Stability and Performance
Authors: Monga K , Rani R , Chaudhary S
Published: November 2021

Perovskite solar cells (PSCs) materials are progressing as potential candidates for the future generation of photovoltaics. Despite the most efficient photovoltaic performance, lead-based perovskite materials are not considered for commercialization due to the high toxicity of lead. One of the promising alternatives is tin (Sn)-based perovskites, which exhibits equivalent ionic size as lead and outstanding absorption properties. However, Sn-based perovskite materials have stability and low-performance issues because of the easy oxidation of Sn2+ to Sn4+and fast crystallization. This paper gives a focused overview of the notable recent studies to address the stability and low-performance challenges of Sn-based hybrid organic-inorganic perovskite (Sn-HOIP) materials for solar cells by using functional additives. To date, the addition of SnF2 additive in the methylammonium tin iodide-based PSCs has shown the highest efficiency of 7.78% and maintains 70% of original efficiency over 200-hours. In the case of formamidinium tin iodide-based PSCs, the addition of phenylhydrazine hydrochloride significantly increases the power conversion efficiency to 11.40% from 5.60% for a pristine device. However, further improvement in the stability and efficiency of Sn-based PSCs requires a molecular-level understanding of the role of existing and new candidates of additives tailored for evolving Sn-HOIP materials.
Zα
Open and Closed Mappings in Double Fuzzy Topological Spaces
Authors: Jayapandian K , Vadivel A , Uma Maheswari O , Sathiyaraj J
Published: November 2021

We introduce and investigate some new class of mappings called double fuzzy Zα-open map and double fuzzy Zα-closed map in double fuzzy topological spaces. Also, some of their fundamental properties are studied. Moreover, we investigate the relationships between double fuzzy Z
α-open and other existing mappings.

AMS (2000) subject classification: 54A40.
Continuous Maps Via ι-fuzzy θ*-semiopen Sets in Ŝtostak’s Fuzzy Topological Spaces
Authors: Mughil A. , Vadivel A. , Uma Maheswari O. , Saravanakumar G.
Published: November 2021

We introduce fuzzy θ*-semicontinuous mappings and relate with fuzzy continuity, fuzzy θ-continuity, fuzzy a-continuity, fuzzy semicontinuity, fuzzy θ-semicontinuity, fuzzy Y-continuity, fuzzy Z-continuity and fuzzy γ-continuity in Ŝostak sense.
Soft e-Separation Axioms in Neutrosophic soft Topological Spaces
Authors: Revathi P. , Chitirakala K. , Vadivel A.
Published: November 2021

In this paper, the idea of neutrosophic soft e-neighbourhood and neutrosophic soft e-separation axioms in neutrosophic soft topological spaces are introduces. Later, we discussed about the concept of neutrosophic soft e-separation axioms of neutrosophic soft topological spaces is diffused in different results with respect to neutrosophic soft points. Furthermore, we discuss the properties of neutrosophic soft e-Ti-spaces (i = 0,1, 2, 3,4) and the relations between them.
Design of Magnetic Circuit for Stationary Plasma Thruster
Authors: Lateef Syed Abdul , Sriram A.T. , Murali Krishnan M. , Sivathanu Pillai A.
Published: November 2021

SPT-100 electrostatic thruster is considered, and the effects of magnetic circuit is studied by introducing magnetic screen. The magnetic flux density in the discharge channel is generated with the help of one inner coil and four outer coils. The radial magnetic field has to be maximum near the exit plane of the thruster to trap the electrons in acceleration region which are emitted from an external hollow cathode. These electrons help in increasing the ionization rate of the propellant gas. This is obtained by placing magnetic poles near exit plane. It helps to traps the electrons emitted from the external hollow cathode. The magnetic circuit should be designed such that the magnetic flux density is near to zero at the anode plane to reduce interaction of electrons with channel walls. To arrive at such better design, magnetic screens are used. Computational simulations are performed to quantify the magnetic flux density distribution along the channel using COMSOL Multiphysics software. The simulation results show that the obtained radial magnetic flux density is maximum near the exit plane, and the magnetic screens help in reducing the magnetic field at the anode region while maintaining the maximum magnetic field at the exit plane.