134 research outputs found
Sub-wavelength diffraction-free imaging with low-loss metal-dielectric multilayers
We demonstrate numerically the diffraction-free propagation of sub-wavelength
sized optical beams through simple elements built of metal-dielectric
multilayers. The proposed metamaterial consists of silver and a high refractive
index dielectric, and is designed using the effective medium theory as strongly
anisotropic and impedance matched to air. Further it is characterised with the
transfer matrix method, and investigated with FDTD. The diffraction-free
behaviour is verified by the analysis of FWHM of PSF in the function of the
number of periods. Small reflections, small attenuation, and reduced Fabry
Perot resonances make it a flexible diffraction-free material for arbitrarily
shaped optical planar elements with sizes of the order of one wavelength.Comment: 5 pages, 4 figure
Induction of Polymerization of the Surface Nanostructures of the Electrodes by Electric Field
The results of experimental studies of the interface of "dielectric liquid - nanostructured metal electrode" after electroconvection is presented. It is discovered the patterns of structuring of areas of polymerization showing disruption of the diffusion layer and the processes of charge injection from the tops of structures.
When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/3636
Novel Optimized Hybrid Terahertz Photoconductive Antennas
We demonstrate the results of on THz emission from hybrid THz photoconductive antenna loaded with silver nanoantenna. The results of experimental investigations are in a good agreement with numerical simulations presented in our recent work. The conversion efficiency reveals over 5-fold improvement at certain frequencies, if compared with similar photoconductive antenna without silver nanoparticles, while previous results for this type of antenna barely exceeded 2-fold conversion efficiency gain. We propose a cost-effective fabrication procedure to realize such hybrid THz antennas with optimized plasmonic nanostructures via thermal dewetting process, which does not require any post processing and makes the proposed solution very attractive for applications
Superstar in Noncommutative Superspace via Covariant Quantization of the Superparticle
A covariant quantization method is developed for the off-shell superparticle
in 10 dimensions. On-shell it is consistent with lightcone quantization, while
off-shell it gives a noncommutative superspace that realizes non-linearly a
hidden 11-dimensional super Poincare symmetry. The non-linear commutation rules
are then used to construct the supersymmetric generalization of the covariant
Moyal star product in noncommutative superspace. As one of the possible
applications, we propose this new product as the star product in supersymmetric
string field theory. Furthermore, the formalism introduces new techniques and
concepts in noncommutative (super)geometry.Comment: 17 pages, LaTe
Visualization of metasurface eigenmodes with magnetic resonance imaging
The ability to control the electromagnetic near field with metasurfaces offers potential applications over the frequency range from radio frequency to optical domains. In this work, we show an essential feature of metasurfaces, subwavelength field confinement via excitation of a large number of eigenstates in a narrow frequency range, and demonstrate an innovative way of visualizing profiles of metasurface eigenmodes with the aid of a magnetic resonance imaging (MRI) system. We show that by tuning different eigenmodes of the metasurface to the Larmor frequency, we can passively tailor the near-field distribution to adjust the desired pattern of radio-frequency excitation in a MRI experiment. Our work demonstrates a practical nonperturbed rapid way of imaging metasurface eigenmodes
An algorithm for measuring wind speed based on sampling aerosol inhomogeneities
Đ Đ°Đ·ŃĐ°Đ±ĐŸŃĐ°Đœ Đ°Đ»ĐłĐŸŃĐžŃĐŒ ĐœĐ° ĐŸŃĐœĐŸĐČĐ” ŃŃĐŒĐżĐ»ĐžŃĐŸĐČĐ°ĐœĐžŃ Đ°ŃŃĐŸĐ·ĐŸĐ»ŃĐœŃŃ
ĐœĐ”ĐŸĐŽĐœĐŸŃĐŸĐŽĐœĐŸŃŃĐ”Đč ĐŽĐ»Ń ĐŸĐ±ŃĐ°Đ±ĐŸŃĐșĐž ĐžĐ·ĐŸĐ±ŃĐ°Đ¶Đ”ĐœĐžĐč ĐČ Đ·Đ°ĐŽĐ°ŃĐ” лОЎаŃĐœĐŸĐłĐŸ ĐžĐ·ĐŒĐ”ŃĐ”ĐœĐžŃ ŃĐșĐŸŃĐŸŃŃĐž ĐČĐ”ŃŃĐ° ĐČ Đ°ŃĐŒĐŸŃŃĐ”ŃĐ”. ĐŃĐŸĐČĐ”ŃĐșĐ° ŃĐ°Đ·ŃĐ°Đ±ĐŸŃĐ°ĐœĐœĐŸĐłĐŸ Đ°Đ»ĐłĐŸŃĐžŃĐŒĐ° ĐżŃĐŸĐžĐ·ĐČĐŸĐŽĐžĐ»Đ°ŃŃ Ń ĐžŃĐżĐŸĐ»ŃĐ·ĐŸĐČĐ°ĐœĐžĐ”ĐŒ ŃĐžĐœŃДзОŃĐŸĐČĐ°ĐœĐœŃŃ
лОЎаŃĐœŃŃ
ŃĐžĐłĐœĐ°Đ»ĐŸĐČ Đž ĐœĐ° ĐŽĐ°ĐœĐœŃŃ
ĐœĐ°ŃŃŃĐœŃŃ
ĐžĐ·ĐŒĐ”ŃĐ”ĐœĐžĐč. ĐĐ»ĐłĐŸŃĐžŃĐŒ ĐŸĐ±ŃĐ°Đ±ĐŸŃĐșĐž Đ°ŃŃĐŸĐ·ĐŸĐ»ŃĐœŃŃ
ĐżĐŸĐ»Đ”Đč ĐČ ĐșĐŸĐŸŃĐŽĐžĐœĐ°ŃĐ°Ń
«ЎалŃĐœĐŸŃŃŃ â ĐČŃĐ”ĐŒŃ» ĐżĐŸĐ·ĐČĐŸĐ»ŃĐ”Ń ŃŃŃĐ”ŃŃĐČĐ”ĐœĐœĐŸ ŃĐŒĐ”ĐœŃŃĐžŃŃ ĐżĐŸĐłŃĐ”ŃĐœĐŸŃŃĐž лОЎаŃĐœĐŸĐłĐŸ ĐČŃĐ”ĐŒŃĐżŃĐŸĐ»ŃŃĐœĐŸĐłĐŸ ĐŒĐ”ŃĐŸĐŽĐ° ĐžĐ·ĐŒĐ”ŃĐ”ĐœĐžŃ ŃĐșĐŸŃĐŸŃŃĐž ĐČĐ”ŃŃĐ° ĐżĐŸ ŃŃĐ°ĐČĐœĐ”ĐœĐžŃ Ń ĐșĐŸŃŃДлŃŃĐžĐŸĐœĐœŃĐŒĐž ĐŒĐ”ŃĐŸĐŽĐ°ĐŒĐž ĐžĐ·ĐŒĐ”ŃĐ”ĐœĐžŃ.
A digital image processing algorithm based on sampling aerosol inhomogeneities was developed in the applied problem of laser remote sensing for measuring the velocity of wind. Tests of the developed algorithm were conducted for synthetic data from numerical simulations and data measured by a lidar. The algorithm developed performs processing of the field of aerosol backscattering coefficient in âRangeTimeâ coordinates and sufficiently increases the measurement accuracy in comparison with correlation methods
Performance of novel VUV-sensitive Silicon Photo-Multipliers for nEXO
Liquid xenon time projection chambers are promising detectors to search for
neutrinoless double beta decay (0), due to their response
uniformity, monolithic sensitive volume, scalability to large target masses,
and suitability for extremely low background operations. The nEXO collaboration
has designed a tonne-scale time projection chamber that aims to search for
0 of \ce{^{136}Xe} with projected half-life sensitivity of
~yr. To reach this sensitivity, the design goal for nEXO is
1\% energy resolution at the decay -value (~keV).
Reaching this resolution requires the efficient collection of both the
ionization and scintillation produced in the detector. The nEXO design employs
Silicon Photo-Multipliers (SiPMs) to detect the vacuum ultra-violet, 175 nm
scintillation light of liquid xenon. This paper reports on the characterization
of the newest vacuum ultra-violet sensitive Fondazione Bruno Kessler VUVHD3
SiPMs specifically designed for nEXO, as well as new measurements on new test
samples of previously characterised Hamamatsu VUV4 Multi Pixel Photon Counters
(MPPCs). Various SiPM and MPPC parameters, such as dark noise, gain, direct
crosstalk, correlated avalanches and photon detection efficiency were measured
as a function of the applied over voltage and wavelength at liquid xenon
temperature (163~K). The results from this study are used to provide updated
estimates of the achievable energy resolution at the decay -value for the
nEXO design
Measurement of the CKM angle in and decays with
A measurement of -violating observables is performed using the decays
and , where the meson is
reconstructed in one of the self-conjugate three-body final states and (commonly denoted ). The decays are analysed in bins of the -decay phase space, leading
to a measurement that is independent of the modelling of the -decay
amplitude. The observables are interpreted in terms of the CKM angle .
Using a data sample corresponding to an integrated luminosity of
collected in proton-proton collisions at centre-of-mass
energies of , , and with the LHCb experiment,
is measured to be . The hadronic
parameters , , , and ,
which are the ratios and strong-phase differences of the suppressed and
favoured decays, are also reported
Measurement of forward charged hadron flow harmonics in peripheral PbPb collisions at âsNN = 5.02 TeV with the LHCb detector
Flow harmonic coefficients,
v
n
, which are the key to studying the hydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions, have been measured in various collision systems and kinematic regions and using various particle species. The study of flow harmonics in a wide pseudorapidity range is particularly valuable to understand the temperature dependence of the shear viscosity to entropy density ratio of the QGP. This paper presents the first LHCb results of the second- and the third-order flow harmonic coefficients of charged hadrons as a function of transverse momentum in the forward region, corresponding to pseudorapidities between 2.0 and 4.9, using the data collected from PbPb collisions in 2018 at a center-of-mass energy of 5.02
TeV
. The coefficients measured using the two-particle angular correlation analysis method are smaller than the central-pseudorapidity measurements at ALICE and ATLAS from the same collision system but share similar features
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