Search

Guided waves are the perfect carriers of electromagnetic signals in planar miniaturized devices due to their high localization and controlled propagation direction. However, it is still a challenge to control the polarization of propagating guided waves. In this work, the broadband polarization TE‐TM degeneracy of highly localized guided waves propagating along an all‐dielectric metasurface and a subwavelength chain of dielectric high‐index cylinders is discovered, both theoretically and experimentally. Using the discovered near‐field polarization degree of freedom, the polarization transformation for guided waves propagating along a subwavelength chain of dielectric cylinders at any frequency within the finite spectral range is demonstrated experimentally. Namely, the simplest planar near‐field polarization device – the quarter‐wave‐retardation (linear‐to‐circular) polarization transformer of guided waves is implemented. The results obtained discover the polarization degree of freedom for guided waves paving the way toward numerous applications in flat optics and planar photonics. [ABSTRACT FROM AUTHOR]

Large varieties of mathematical programming models have been developed to provide decision support to the design engineer. The paper deals with some of the problems and offers practical solutions. [ABSTRACT FROM AUTHOR]

Absorption of electromagnetic energy by a dissipative material is one of the most fundamental electromagnetic processes that underlies a plethora of applied problems, including sensing, radar detection, wireless power transfer, and photovoltaics. Common wisdom is that a finite dissipative object illuminated by a plane wave removes only a finite amount of the wave's energy flux, which is determined by the object's absorption cross‐section. Thus, it is of fundamental interest to see if any far‐field waveform can be perfectly absorbed by a finite object. Here, it is theoretically demonstrated that a precisely tailored light beam containing only far‐field components can be perfectly absorbed by a finite scatterer on a substrate. The self‐consistent scattering problem in the dipole approximation is analytically solved and finds a closed‐form expression for the spatial spectrum of the incident field and the required complex polarizability of the particle. All analytical predictions are confirmed with full‐wave simulations. The results introduce a qualitatively novel class of perfect absorption phenomena in electromagnetics and other wave processes. [ABSTRACT FROM AUTHOR]

Objective: To present a novel surgical approach to performing bulbar urethroplasty and to assess its initial outcomes and safety.Materials and Methods: From January 2016 to March 2019, anastomotic urethroplasty without full mobilization and dissection of corpus spongiosum dorsal semicircumference was performed in 8 males with bulbar strictures by a single surgeon. Patients were given uroflowmetry, urethrography, and International Index of Erectile Function (IIEF) questionnaires at their 3- and 12- month follow-up visits postoperatively.Results: Mean stricture length was 2.3 cm (±0.59 cm) and mean surgery time was 131 minutes. No early or late postoperative complications were observed. Median maximum flow rate (Qmax) assessed 3 months after surgery was 22.35 mL/sec (±6.4 mL/sec). There were no significant changes in median IIEF score postoperatively (preoperative IIEF = 18.4 vs postoperative IIEF = 19.6; P >.05). During patients' 1-year observation period, no signs of constriction in the anastomosis were revealed with urethrography. One of the limitations of this technique is a necessity of more precise corpus spongiosum preparation to ensure perioperative hemostasis and good visualization. This outcome may, however, require additional time and increased blood loss during a surgeon's learning curve of the procedure.Conclusion: The initial experience of this minimally invasive urethroplasty technique showed high efficiency and no early stricture recurrences. However, the clinical significance of additional preservation of innervation and blood supply, the potential to further optimize this technique's functional outcomes, and applicability of this technique in patients with spongiofibrosis requires further investigation. Our results make it possible to consider this technique as a possible alternative to classic anastomotic urethroplasty. [ABSTRACT FROM AUTHOR]

The report analyzes the possibility of using analytic hierarchy process in logistics demand forecasting. It proposes a method to estimate parameters of the individual values of the analysis. [ABSTRACT FROM AUTHOR]

We discuss the recent advances in meta-optics and nanophotonics associated with the physics of bound states in the continuum (BICs). Such resonant states appear due to a strong coupling between leaky modes in optical guiding structures being supported by subwavelength high-index dielectric Mie-resonant nanoantennas or all-dielectric metasurfaces. First, we review briefly very recent developments in the BIC physics in application to isolated subwavelength particles. We pay a special attention to novel opportunities for nonlinear nanophotonics due to the large field enhancement inside the particle volume creating the resonant states with high-quality (high- Q) factors, the so-called quasi-BIC, that can be supported by the subwavelength particles. Second, we discuss novel applications of the BIC physics to all-dielectric optical metasurfaces with broken-symmetry meta-atoms when tuning to the BIC conditions allows to enhance substantially the Q factor of the flat-optics dielectric structures. We also present the original results on nonlinear high- Q metasurfaces and predict that the frequency conversion efficiency can be boosted dramatically by smart engineering of the asymmetry parameter of dielectric metasurfaces in the vicinity of the quasi-BIC regime. [ABSTRACT FROM AUTHOR]

Surface electromagnetic waves are characterized by the intrinsic spin-orbit interaction which results in the fascinating spin-momentum locking. Therefore, directional coupling of light to surface waves can be achieved through chiral nanoantennas. Here, we show that dielectric nanoantenna provides chiral response with strong spectral dependence due to the interference of electric and magnetic dipole momenta when placed in the vicinity of the metal-air interface. Remarkably, chiral behaviour in the proposed scheme does not require elliptical polarization of the pump beam or the geometric chirality of the nanoantenna. We show that the proposed ultracompact and simple dielectric nanoantenna allows for both directional launching of surface plasmon polaritons on a thin gold film and their demultiplexing with a high spectral resolution. [ABSTRACT FROM AUTHOR]

The shortest path problem is one of the fundamental network flow problems. A large number of problems from diverse areas such as routing in telecommunication networks are an intrinsic part of this problem. The report examines different algorithms to solve this major problem for logistics. [ABSTRACT FROM AUTHOR]

Organizations and enterprises around the world differ greatly in terms of mission, scale, and scope. Yet all of them aim to deploy the best possible network of facilities worldwide for developing, producing, distributing, selling and servicing their products and offers to their targeted markets and clients. Underlying this continuous quest for optimal network deployment is the facility location and layout design engineering. [ABSTRACT FROM AUTHOR]

The report analyzes the possibility of using analytic hierarchy process in logistics demand forecasting. It proposes a method to estimate parameters of the individual values of the analysis. [ABSTRACT FROM AUTHOR]

Warehouse operations are much more complex than when they appear at first glance. Profiling (partitioning) of products and orders leads to a potential multitude of warehouses inside the warehouse. The paper presents an algorithm for increasing storage capacity in modern warehouses. [ABSTRACT FROM AUTHOR]

Unusual optical properties of laser-ablated metal surfaces arise from the excitation of local plasmon resonances in nano- and microstructures produced by laser-processing and from the mutual interaction of those structures through surface plasmon polariton (SPP) waves. This interaction provides a synergistic effect, which can make the optical properties of the composite nanostructure drastically different from the properties of its elements. At the same time, the prediction and analysis of these properties are hampered by the complexity of the analytical solution to the problem of SPP excitation by surface objects of arbitrary configuration. Such a problem can be reduced to a simpler one if one considers the geometry of a structured surface as a superposition of harmonic Fourier components. Therefore, the analytical solution to the problem of surface plasmon polariton excitation through the scattering of light by a sinusoidally perturbed plasmonic metal/vacuum boundary becomes very important. In this work, we show that this problem can be solved using a well-known method for calculating guided-mode amplitudes in the presence of current sources, which is used widely in the waveguide theory. The calculations are carried out for the simplest 2D cases of (1) a sinusoidal current of finite length and (2) a finite-length sinusoidal corrugation on a plasmonic metal surface illuminated by a normally incident plane wave. The analytical solution is compared with the results of numerical simulations. It is shown that, in the first case, the analytical and numerical solutions agree almost perfectly. In the second case, the analytical solution correctly predicts the optimum height of the corrugation x opt , providing the maximum SPP excitation efficiency. At the same time, the analytical and numerical values of the SPP amplitude agree very well when the corrugation height x turns out to be x ≪ x opt or x ≫ x opt (at least up to 3 x opt ); at x = x opt , the mismatch of those does not exceed 25%. The limitations of the analytical model leading to such a mismatch are discussed. We believe that the presented approach is useful for modeling various phenomena associated with SPP excitation. [ABSTRACT FROM AUTHOR]

The design of secure yet efficiently implementable cryptographic algorithms is a fundamental problem of cryptography. Lately, lightweight cryptography--optimizing the algorithms to fit the most constrained environments--has received a great deal of attention, the recent research being mainly focused on building block ciphers. As opposed to that, the design of lightweight hash functions is still far from being well investigated with only few proposals in the public domain. In this paper, we aim to address this gap by exploring the design space of lightweight hash functions based on the sponge construction instantiated with present-type permutations. The resulting family of hash functions is called spongent. We propose 13 spongent variants--or different levels of collision and (second) preimage resistance as well as for various implementation constraints. For each of them, we provide several ASIC hardware implementations--ranging from the lowest area to the highest throughput. We make efforts to address the fairness of comparison with other designs in the field by providing an exhaustive hardware evaluation on various technologies, including an open core library. We also prove essential differential properties of spongent permutations, give a security analysis in terms of collision and preimage resistance, as well as study in detail dedicated linear distinguishers. [ABSTRACT FROM AUTHOR]

The paper considers the application of ready - made integrated complex systems for logistic management of goods and information flows. It deals with the integration of the conceptual approach with the production and operational management. Thus the market situation analysis is done which helps proper decision making. Different structures of a computer based system for storage management are analyzed. [ABSTRACT FROM AUTHOR]

The paper deals with the potential for meeting the requirements for proper storage in different firms and companies. It analyses the advantages of all kinds of storage, depending on the specific conditions. Different ways of compensating the disadvantages of certain storage are given. Different ways of cost reduction are suggested. Some of them include grouping the cargo units. [ABSTRACT FROM AUTHOR]

The substitution for Arg168His (R168H) in γ-tropomyosin (TPM3 gene, Tpm3.12 isoform) is associated with congenital muscle fiber type disproportion (CFTD) and muscle weakness. It is still unclear what molecular mechanisms underlie the muscle dysfunction seen in CFTD. The aim of this work was to study the effect of the R168H mutation in Tpm3.12 on the critical conformational changes that myosin, actin, troponin, and tropomyosin undergo during the ATPase cycle. We used polarized fluorescence microscopy and ghost muscle fibers containing regulated thin filaments and myosin heads (myosin subfragment-1) modified with the 1,5-IAEDANS fluorescent probe. Analysis of the data obtained revealed that a sequential interdependent conformational-functional rearrangement of tropomyosin, actin and myosin heads takes place when modeling the ATPase cycle in the presence of wild-type tropomyosin. A multistep shift of the tropomyosin strands from the outer to the inner domain of actin occurs during the transition from weak to strong binding of myosin to actin. Each tropomyosin position determines the corresponding balance between switched-on and switched-off actin monomers and between the strongly and weakly bound myosin heads. At low Ca2+, the R168H mutation was shown to switch some extra actin monomers on and increase the persistence length of tropomyosin, demonstrating the freezing of the R168HTpm strands close to the open position and disruption of the regulatory function of troponin. Instead of reducing the formation of strong bonds between myosin heads and F-actin, troponin activated it. However, at high Ca2+, troponin decreased the amount of strongly bound myosin heads instead of promoting their formation. Abnormally high sensitivity of thin filaments to Ca2+, inhibition of muscle fiber relaxation due to the appearance of the myosin heads strongly associated with F-actin, and distinct activation of the contractile system at submaximal concentrations of Ca2+ can lead to muscle inefficiency and weakness. Modulators of troponin (tirasemtiv and epigallocatechin-3-gallate) and myosin (omecamtiv mecarbil and 2,3-butanedione monoxime) have been shown to more or less attenuate the negative effects of the tropomyosin R168H mutant. Tirasemtiv and epigallocatechin-3-gallate may be used to prevent muscle dysfunction. [ABSTRACT FROM AUTHOR]

The paper addresses the enumeration problem for k-tangles. We introduce the notion of a cascade diagram of a k-tangle projection and suggest an effective enumeration algorithm for projections based on the cascade representation. Tangle projections and alternating tangles with up to 12 crossings are tabulated. We also provide pictures of alternating k-tangles with at most five crossings. [ABSTRACT FROM AUTHOR]

In 2007, the US National Institute for Standards and Technology (NIST) announced a call for the design of a new cryptographic hash algorithm in response to vulnerabilities like differential attacks identified in existing hash functions, such as MD5 and SHA-1. NIST received many submissions, 51 of which got accepted to the first round. 14 candidates were left in the second round, out of which five candidates have been recently chosen for the final round. An important criterion in the selection process is the SHA-3 hash function security. We identify two important classes of security arguments for the new designs: (1) the possible reductions of the hash function security to the security of its underlying building blocks and (2) arguments against differential attack on building blocks. In this paper, we compare the state of the art provable security reductions for the second round candidates and review arguments and bounds against classes of differential attacks. We discuss all the SHA-3 candidates at a high functional level, analyze, and summarize the security reduction results and bounds against differential attacks. Additionally, we generalize the well-known proof of collision resistance preservation, such that all SHA-3 candidates with a suffix-free padding are covered. [ABSTRACT FROM AUTHOR]

The reactions of such cyclic α-diketones as acenaphthenequinone, aceanthrenequinone, and N-alkylisatins, with hexaethyltnaminophosphine in the presence of the fullerene C60 lead to the formation of methanotullerene derivatives under mild conditions. This process proceeds via deoxygenation of the dicarbonyl compound by the P(III) derivative and is likely to involve the intermediate formation of α-ketocarbenes. The structure of some methanofullerenes has been confirmed by NMR and XRD. The electrochemical behavior of the methanofullerenes was also investigated. [ABSTRACT FROM AUTHOR]

Two new algorithms for robust and fault-tolerant classifier combination are presented. The attractor dynamics (AD) algorithm models some properties of sensory integration in the central nervous system and is based on the application of the dynamical systems for classifier fusion. The classifier masking (CM) algorithm is a nonneural version of the AD algorithm based on finding intersecting classifier intervals. Both of the proposed algorithms employ the idea of consensus among individual classifiers. The individual classifiers have been trained using resampled feature sets. They fuse the information from Advanced Synthetic Aperture Radar, Medium Resolution Imaging Spectrometer, and Advanced Along Track Scanning Radiometer Envisat satellite sensors for the improved sea ice classification. The results of our experiments show that training and combing the individual classifier outputs in a multiple classifier system significantly improve the robustness and the fault tolerance of the classification system as compared to the single classifier combining all sources of information. The robustness of the single classifier has been largely reduced in cases of single sensor failures (87.9% in normal conditions versus 64.8% and 66.1% for two artificially corrupted data sets), whereas the CM algorithm is more tolerant to the sensor and preprocessing errors (86.4% in normal conditions versus 78.9% and 73.6% for two artificially corrupted data sets). The performance of the CM algorithm is superior to those of the simple multiple classifier combination strategies based on classifier averaging and majority voting (78.9% versus 70.9% and 69.5%, respectively) because the AD and CM algorithms are able to discard the corrupted classifier outputs based on classifier agreement and, in fact, represent hybrid approaches combining the properties of classifier averaging and classifier selection methods. [ABSTRACT FROM AUTHOR]

The control of light through all‐optical means is a fundamental challenge in nanophotonics and a key effect in optical switching and logic. The optical bistability effect enables this control and can be observed in various planar photonic systems such as microdisk and photonic crystal cavities and waveguides. However, the recent advancements in flat optics with wavelength‐thin optical elements require nonlinear elements based on metastructures and metasurfaces. The performance of these systems can be enhanced with high‐Q bound states in the continuum (BIC), which leads to intense harmonic generation, improved light‐matter coupling, and pushes forward sensing limits. This study reports enhanced thermo‐optical nonlinearity and the observation of optical bistability in an all‐dielectric metasurface membrane with BIC. Unlike many other nanophotonic platforms, metasurfaces allow for fine control of the quality factor of the BIC resonance by managing the radiative losses. This provides an opportunity to control the parameters of the observed hysteresis loop and even switch from bistability to optical discrimination by varying the angle of incidence. Additionally, this work proposes a mechanism of nonlinear critical coupling that establishes the conditions for maximal hysteresis width and minimal switching power, which has not been reported before. The study suggests that all‐dielectric metasurfaces supporting BICs can serve as a flat‐optics platform for optical switching and modulation based on strong thermo‐optical nonlinearity. [ABSTRACT FROM AUTHOR]

Raman lasers are an actively developing field of nonlinear optics aiming to create efficient frequency converters and various optical sensors. Due to the growing importance of ultracompact chip‐scale technologies, there is a constant demand for optical device miniaturization; however, the development of a nanoscale Raman laser remains a challenging endeavor. In this work, a fully subwavelength Raman laser operating in visible range is proposed, based on a gallium phosphide nanocylinder resonator supporting a quasi‐bound state in the continuum (quasi‐BIC). The precise spectral matching of the nanoparticle high‐Q modes is performed with the pump and detuned Raman emission wavelengths. The simulations demonstrate an experiment‐ready design of Raman nanolaser with a lasing threshold expected to be as low as Pth≈21mW$P_{\mathrm{th}} \approx 21\nobreakspace \mathrm{mW}$. The proposed configuration represents the prototype of a low‐threshold Raman nanolaser with all dimensions smaller than the operational wavelength. [ABSTRACT FROM AUTHOR]

The key components of photonic integrated circuits are nanoscale optica emitters and nanowaveguides. III‐V semiconductor nanostructures are considered as the most promising material platform for these components due to highly efficient luminescence and high refractive index, but the problem of emission coupling with waveguide is to be solved. In this work, the use of GaP nanowires (NWs) with different types of doping (GaP:Si or GaP:Be) is proposed as optical waveguides with directly integrated electrically‐driven light sources, solving the problem of emission‐to‐waveguide coupling. Single NWs are integrated with electrodes and pump electroluminescence by a tunnel junction allowing to study emission properties with nanoscale spatial resolution. Basing on the experiments on scanning tunnelling microscopy (STM), electron microscopy, time‐resolved photoluminescence micro‐spectroscopy, X‐ray diffraction, and STM‐induced electroluminescence, it is proven that GaP NWs exhibit different integrated light‐source on doping type of NWs. GaP:Be NWs contain inclusion of the crystalline wurtzite phase with a direct bandgap, and, thus, these NW regions can be considered as electrically‐driven nanoscale sources of light monolithically integrated into GaP NW‐based waveguides. Meanwhile, GaP:Si NWs work as optical waveguides capable of efficient light generation over the entire length of NW. The developed designs are promising for construction of integrated photonic circuits. [ABSTRACT FROM AUTHOR]

Wireless sensors find use in many practical applications, where wired connections possess a limitation. New realms of global connectivity and data exchange among various devices suggest putting a sensor on a consumable level, where electronic circuits are not affordable from an economic standpoint. Chipless approaches, aiming to address the later issue, typically come with a penalty of performance degradation and, in many cases, is seen as a compromise solution. Here, we demonstrate a concept of the extremely sensitive temperature sensor based on the bound states in the continuum (BIC) approach. A ceramic half-cylinder above a ground plane is designed to support high quality factor supercavity modes with a strong resonant dependence on an ambient temperate. The operation of the sensor is experimentally demonstrated in a broad range of temperatures, spanning from 25 to 105 °C with an average sensitivity of 4 MHz/°C. The key element, leading to this performance, is high-quality ceramics, which allows supporting confined modes with moderately low Ohmic losses and extremely high-quality factors above 1000. High-performance chipless devices, which are capable to accommodate several functions with a single platform, open a venue to a new generation of wireless distributed sensors, where the main technological and outlay efforts are placed on an interrogation side. [ABSTRACT FROM AUTHOR]

Germanium self‐assembled nanoislands and quantum dots are very prospective for CMOS‐compatible optoelectronic integrated circuits but their photoluminescence (PL) intensity is still insufficient for many practical applications. Here, it is demonstrated experimentally that the PL of Ge nanoislands in silicon photonic crystal slabs (PCS) with hexagonal lattice can be dramatically enhanced due to the involvement in the emission process of the bounds states in the continuum. These high‐Q photonic resonances allow to achieve PL resonant peaks with the quality factor as high as 2200 and with the peak PL enhancement factor of more than two orders of magnitude. The corresponding integrated PL enhancement is demonstrated to be more than one order of magnitude. This effect is studied theoretically by the Fourier modal method in the scattering matrix form. The symmetry of the quasi‐normal guided modes in the PCS is described in terms of group theory. This work paves the way toward a new class of optoelectronic components compatible with silicon technology. [ABSTRACT FROM AUTHOR]

Optomechanical manipulation of micro and nano-scale objects with laser beams finds use in a large span of multidisciplinary applications. Auxiliary nanostructuring could substantially improve performances of classical optical tweezers by means of spatial localization of objects and intensity required for trapping. Here we investigate a three-dimensional nanorod metamaterial platform, serving as an auxiliary tool for the optical manipulation, able to support and control near-field interactions and generate both steep and flat optical potential profiles. It was shown that the 'topological transition' from the elliptic to hyperbolic dispersion regime of the metamaterial, usually having a significant impact on various light-matter interaction processes, does not strongly affect the distribution of optical forces in the metamaterial. This effect is explained by the predominant near-fields contributions of the nanostructure to optomechanical interactions. Semi-analytical model, approximating the finite size nanoparticle by a point dipole and neglecting the mutual re-scattering between the particle and nanorod array, was found to be in a good agreement with full-wave numerical simulation. In-plane (perpendicular to the rods) trapping regime, saddle equilibrium points and optical puling forces (directed along the rods towards the light source), acting on a particle situated inside or at the nearby the metamaterial, were found. [ABSTRACT FROM AUTHOR]

Here, we introduce and demonstrate nanoprinted all-dielectric nanostructures located on fiber end faces as a novel concept for the efficient coupling of light into optical fibers, especially at multiple incidence angles and across large angular intervals. Taking advantage of the unique properties of the nanoprinting technology, such as flexibly varying the width, height, and gap distance of each individual element, we realize different polymeric axial-symmetric structures, such as double-pitch gratings and aperiodic arrays, placed on the facet of commercial step-index fibers. Of particular note is the aperiodic geometry, enabling an unprecedentedly high average coupling efficiency across the entire angular range up to 80°, outperforming regular gratings and especially bare fibers by orders of magnitude. The excellent agreement between simulation and experiment clearly demonstrates the quality of the fabricated structures and the high accuracy of the nanoprinting process. Our approach enables realizing highly integrated and ready-to-use fiber devices, defining a new class of compact, flexible, and practically relevant all-fiber devices beyond the state-of-art. Applications can be found in a variety of cutting-edge fields that require highly efficient light collection over selected angular intervals, such as endoscopy or quantum technologies. Furthermore, fiber functionalization through nanoprinting represents a promising approach for interfacing highly complex functional photonic structures with optical fibers. [ABSTRACT FROM AUTHOR]

The problem of extracting the highest possible amount of key-related information using the lowest possible number of measurements is one of the central questions in side-channel attacks against embedded implementations of cryptographic algorithms. To address it, this work proposes a novel framework enhancing side-channel collision attacks with divide-and-conquer attacks such as differential power analysis (DPA). An information-theoretical metric is introduced for the evaluation of collision detection efficiency. Improved methods of dimension reduction for side-channel traces are developed based on a statistical model of euclidean distance. Experimental results confirm that DPA-combined collision attacks are superior to both DPA-only and collision-only attacks. The new methods of dimension reduction lead to further complexity improvements. All attacks are treated for the case of AES-128 and are practically validated on a widespread 8-bit RISC microcontroller. [ABSTRACT FROM AUTHOR]

Noise pollution remains a challenging problem requiring the development of novel systems for noise insulation. Extensive work in the field of acoustic metamaterials has led to various ventilated structures which, however, are usually demonstrated for rather narrow regions of the audible spectrum. In this work, the idea of metamaterial‐based systems is further extended, developing the concept of a metahouse chamber representing a ventilated structure for multiple band noise insulation. Broad stop‐bands originate from strong coupling between pairs of Helmholtz resonators constituting the structure. The averaged transmission −18.6 dB are demonstrated numerically and experimentally within the spectral range from 1500 to 16 500 Hz. The sparseness of the structure together with the possibility to use optically transparent materials suggest that the chamber may be also characterized by partial optical transparency depending on the mutual position of structural elements. The obtained results are promising for development of novel noise‐insulating structures advancing urban science. [ABSTRACT FROM AUTHOR]

We reveal unusually strong polarization sensitivity of electric and magnetic dipole resonances of high-index dielectric nanoparticles placed on a metallic film. By employing dark-field spectroscopy, we observe the polarization-controlled transformation from high-Q magnetic-dipole scattering to broadband suppression of scattering associated with the electric dipole mode, and show numerically that it is accompanied by a strong enhancement of the respective fields by the nanoparticle. Our experimental data for silicon nanospheres are in an excellent agreement with both analytical calculations based on Green's function approach and the full-wave numerical simulations. Our findings further substantiate dielectric nanoparticles as strong candidates for many applications in enhanced sensing, spectroscopy and nonlinear processes at the nanoscale. [ABSTRACT FROM AUTHOR]

We demonstrate both analytically and numerically the existence of optical pulling forces acting on particles located near plasmonic interfaces. Two main factors contribute to the appearance of this negative recoil force. The interference between the incident and reflected waves induces a rotating dipole with an asymmetric scattering pattern, while the directional excitation of surface plasmon polaritons (SPPs) enhances the linear momentum of scattered light. The strongly asymmetric SPP excitation is determined by spin-orbit coupling of the rotating dipole and surface plasmon polariton. As a result of the total momentum conservation, the force acting on the particle points in a direction opposite to the incident wave propagation. We derive analytical expressions for the force acting on dipolar particles placed in the proximity of plasmonic surfaces. Analytical expressions for this pulling force are derived within the dipole approximation and are in excellent agreement with results of electromagnetic numerical calculations. The forces acting on larger particles are analyzed numerically, beyond the dipole approximation. [ABSTRACT FROM AUTHOR]

The reaction of 2-(5-methyl-2-phenyl-2H-1,2,3-dizaphosphol-4-yl)-4H-benzo[d]-1,3,2-dioxaphosphorin-4-one with arylimines leads to the formation of seven-membered heterocycles, 3-aryl-2-(5-methyl-2-phenyl-2H-1,2,3-dizaphosphol-4-yl)benzo[f]-1,4,2-oxaza-phosphepin-5-ones with moderate stereoselectivity. 1,2,3-Diazaphospholic moiety does not take part in the process and fulfills the role of sterically hindered substituent. [ABSTRACT FROM PUBLISHER]

Huygens' metasurfaces (HMS) without any reflection or transmission are widely studied due to the high-efficiency manipulation of electromagnetic waves. In this work, three-layered metallic Huygens' metasurfaces are proposed and the geometry-dependences of anomalous refraction and reflection are investigated. The surface impedance and admittance are independently tailored by changing the length of metallic resonators, which is dictated by the introduction of the intermediate layer. Huygens' metasurfaces can be geometrically engineered to realize anomalous refraction with an efficiency of 62% and anomalous reflection with an efficiency of 60%, respectively. It is anticipated that the proposed metasurface with tunable materials could achieve reconfigurable terahertz devices. • The surface impedance and admittance can be independently controlled by adjusting the lengths of the intermediate metal layer resonators. • With the introduction of the intermediate layer, Huygens' metasurfaces can be geometrically engineered to realize anomalous refraction with an efficiency of 62%. • With the introduction of the intermediate layer, Huygens' metasurfaces can be geometrically engineered to realize anomalous reflection with an efficiency of 60%. [ABSTRACT FROM AUTHOR]

Abstract: Solving systems of linear equations (SLEs) is a very common computational problem appearing in numerous research disciplines and in particular in the context of cryptographic and cryptanalytic algorithms. In this work, we present highly efficient hardware architectures for solving (small and medium-sized) systems of linear equations over . These architectures feature linear or quadratic running times with quadratic space complexities in the size of an SLE, and can be clocked at high frequencies. Among the most promising architectures are one-dimensional and two-dimensional systolic arrays which we call triangular systolic and linear systolic arrays. All designs have been fully implemented for different sizes of SLEs and concrete FPGA implementation results are given. Furthermore, we provide a clear comparison of the presented SLE solvers. The significance of these designs is demonstrated by the fact that they are used in the recent literature as building blocks of efficient architectures for attacking block and stream ciphers (Bogdanov et al., 2007 ; Geiselmann et al., 2009 ) and for developing cores for multivariate signature schemes (Balasubramanian et al., 2008 ; Bogdanov et al., 2008 ). [Copyright &y& Elsevier]

Since surface plasmon polaritons (SPPs) are surface waves, they cannot be excited by an incident plane wave, because free-space photons do not possess a sufficient in-plane momentum. Phase matching between the incident light and SPP can be achieved using a high-refractive-index prism, grating, or nanoantennas. In this work, we found an expression for the amplitude of SPP excited by an arbitrary 3D current distribution placed near a metal interface. The developed method is based on the well-known technique used in waveguide theory that enables finding the amplitudes of waveguide modes excited by the external currents. It reduces the SPP excitation problem to the summation of the set of emitters. As a particular example, we considered a spherical dipole nanoantenna on a metal substrate illuminated by a normally incident plane wave. The analytical calculations were in good agreement with the full-wave numerical simulations. [ABSTRACT FROM AUTHOR]

Enhancing Photoluminescence: Photonic Bound States in the Continuum in Si Structures with the Self-Assembled Ge Nanoislands (Laser Photonics Rev. 15(7)/2021) The cover image illustrates the photonic crystal slab's eigenmode as demonstrated in article number 2000242 by Sergey Dyakov and co-workers. From this figure, one can determine the symmetry type of this mode and predict the features of the far-field emissivity of quantum emitters at the corresponding frequency. [Extracted from the article]

Radio frequency identification (RFID) is a widely used technology for contactless data readout. Numerous passive RFID tags are available on the market, and in a vast majority of cases, their designs are based on flat meandered dipole architectures. However, besides technological advantages, those realizations suffer from polarization mismatch issues and limited spatial sectors, from which flat tags can be interrogated. Here, we demonstrate and analyze a miniature omnidirectional tag accessible from all 4π stereo angles with a commercial RFID reader. Our design is based on exploring all three dimensions, which allows achieving close to perfect angular coverage by overlapping several multipole resonances of a structure. An optimized metal strip with a nontrivial geometry is wrapped on a high permittivity ceramic sphere for miniaturization purposes. As a result, a 3 cm device (tenths of an operational wavelength) is demonstrated to be readable from a 1.5 m distance without any dependence on the interrogation direction. Compact omnidirectional tags can remove hard restrictions on a mutual orientation between information holders and interrogating systems. Those capabilities are essential in many applications, including logistics, animal activity monitoring, and security, to name just a few. [ABSTRACT FROM AUTHOR]

Radio frequency identification (RFID) is a mature technology that allows contactless reading of data via a wireless communication link. While communication protocols in this field are subject to international regulations, there are plenty of opportunities to improve hardware realization of antenna devices that support this technology. In particular, readout range extension and miniaturization of passive RFID tags is an important challenge with far-reaching goals. Here, we introduce and analyze a new concept of high-permittivity ceramic tag that relies on different physical principles. Instead of using conduction currents in metallic wires to drive electronic chips and generate electromagnetic radiation, high-permittivity components rely on excitation of displacement currents. Those are efficiently converted to actual electric current which drives the memory chip. Practical aspects of this approach are improved robustness to environmental fluctuations, footprint reduction, and readout range extension. In particular, our high-permittivity ceramic (ε ~ 100) elements have demonstrated a 25% reading range improvement in comparison to commercial tags. In case when state-of-the-art readers and RFID chips are used, the readout distances of the developed ceramic tags can reach 22 m. This number can be further extended with improved matching circuits. Miniature RFID tags, capable to establish long-range communication channels, can find use in many applications, including retail, security, Internet of Things, and many others. [ABSTRACT FROM AUTHOR]

Subwavelength optical resonators made of high-index dielectric materials provide efficient ways to manipulate light at the nanoscale through mode interferences and enhancement of both electric and magnetic fields. Such Mie-resonant dielectric structures have low absorption, and their functionalities are limited predominantly by radiative losses. We implement a new physical mechanism for suppressing radiative losses of individual nanoscale resonators to engineer special modes with high quality factors: optical bound states in the continuum (BICs). We demonstrate that an individual subwavelength dielectric resonator hosting a BIC mode can boost nonlinear effects increasing second-harmonic generation efficiency. Our work suggests a route to use subwavelength high-index dielectric resonators for a strong enhancement of light–matter interactions with applications to nonlinear optics, nanoscale lasers, quantum photonics, and sensors. [ABSTRACT FROM AUTHOR]