Topological engineering of interfacial optical Tamm states for highly-sensitive near-singular-phase optical detection

We developed planar multilayered photonic-plasmonic structures, which support topologically protected optical states on the interface between metal and dielectric materials, known as optical Tamm states. Coupling of incident light to the Tamm states can result in perfect absorption within one of several narrow frequency bands, which is accompanied by a singular behavior of the phase of electromagnetic field. In the case of near-perfect absorptance, very fast local variation of the phase can still be engineered. In this work, we theoretically and experimentally demonstrate how these drastic phase changes can improve sensitivity of optical sensors. A planar Tamm absorber was fabricated and used to demonstrate remote near-singular-phase temperature sensing with an over an order of magnitude improvement in sensor sensitivity and over two orders of magnitude improvement in the figure of merit over the standard approach of measuring shifts of resonant features in the reflectance spectra of the same absorber. Our experimentally demonstrated phase-to-amplitude detection sensitivity improvement nearly doubles that of state-of-the-art nano-patterned plasmonic singular-phase detectors, with further improvements possible via more precise fabrication. Tamm perfect absorbers form the basis for robust planar sensing platforms with tunable spectral characteristics, which do not rely on low-throughput nano-patterning techniques.Comment: 31 pages; 6 main text figures and 10 supplementary figure

Hyperspectral images neural network analysis of unstained micropreparations

The article presents the results of a study of hyperspectral imaging in microscopy to assess pathological changes in unstained medical micropreparations.Hyperspectral imaging was carried out using a system of synchronous shooting and movement of a movable table combined with a stepper motor. To improve the quality of theobtained images, software correction of the illumination of the spectral channels was used. The classification was carried out by a convolutional neural network. This method may be promising for assessing pathological changes in clinical practice. Experimental studies were carried out on histological preparations with different types of tissues without staining with contrasting medical dyes. To assess the reliability of the classification method, a comparison was made with thestandard method using staining of the studied samples

Topological Darkness of Tamm Plasmons for High-Sensitivity Singular-Phase Optical Detection

Multilayered photonic-plasmonic structures exhibit topologically protected zero reflection if they are designed to support Tamm plasmon modes. Sharp phase changes associated with the Tamm mode excitation dramatically improve sensitivity of detectors

Resonance lens antenna analysis for MM-wave applications

We report what is to our knowledge the first accurate theoretical investigation of the electromagnetic behavior of 2-D elliptical lenses of finite wavelength-scale size. The role of internal resonances in the focal domain formation is studied. A proposal of a narrow-band receiver based on a hemielliptic lens tuned to a resonance is discussed. Possible features of such a lens-coupled receiver are stability of the resonance field with respect to the angle of arrival of incident wave and several times greater values of the peak field intensity that may potentially lead to higher sensitivity and better scanning performance. In the analysis, we use the Muller boundary integral equation (BIE) technique. This full-wave mathematically rigorous method is combined with trigonometric Galerkin discretization to result in the efficient numerical solution for an arbitrary set of the electrical, geometrical, and material parameters. Numerical results are generated for a quartz elliptical lens (ε= 3.8) with dimensions typical to mm-wave radar applications. Near field analysis, lens-focusing properties and lens frequency-dependent performance are presented

Lens or resonator? Electromagnetic behavior of an extended hemielliptic lens for a sub-millimeter-wave receiver

The behavior of a 2D model of an extended hemielliptic silicon lens of a size typical for THz applications is accurately studied for the case of a plane E-wave illumination. The full-wave analysis of the scattering problem is based on the Mutter's boundary integral-equations (MB1E) that are uniquely solvable. A Calerkin discretization scheme with a trigonometric basis leads tu a very efficient numerical algorithm. The numerical results related to the focusability of the lens versus its rear-side extension and the angle of the plane-wave incidence, as well as near-field profiles, demonstrate strong resonances. Such effects can change the principles of optimal design of lens-based receivers. © 2004 Wiley Periodicals, Inc

The control system for radiation sterilization of health-care products at the accelerator LU-10

The regulatory documents for the technological process of sterilization (DSTU ISO 11 137:2003 and others) set requirements on monitoring, maintaining and archiving the basic parameters of the process. To meet the requirements, an automated control system was created at the LU-10. It includes a PC-controlled beam scanner, technological measuring channels (TMC), and also a set of working standards to calibrate the channels. The CAMAC standard was used as an interface. The software of the complex provides the real-time processing of information on the beam parameters, their control, archiving, and also the information exchange within the local-area technological network. The presence of the Customer Database comprising the characteristics of incoming products makes it possible to optimize the process conditions for the products by the computer simulation method.Нормативные документы на технологический процесс стерилизации (ДСТУ ISO 11 137:2003 и др.) устанавливают требования мониторирования, поддержания и архивирования основных параметров процесса. Для удовлетворения этим требованиям на ЛУ-10 создана автоматизированная система контроля. В ее состав входит управляемый РС сканер пучка, технологические измерительные каналы, а также набор рабочих эталонов для калибровки каналов. В качестве интерфейса использован стандарт КАМАК. Программное обеспечение комплекса дает возможность в режиме реального времени производить обработку информации о параметрах пучка, управлять ими, их архивировать, а также обмениваться информацией в пределах локальной технологической сети. Наличие базы данных «Заказчик» с характеристиками поступающей продукции позволяет оптимизировать режим ее обработки методом компьютерного моделирования.Нормативні документи на технологічний процес стерилізації (ДСТУ ISO 11 137:2003 та інші) установлюють вимоги моніторування, підтримки і архивування основних параметрів процесу. Для задоволення цим вимогам на ЛП-10 створена автоматизована система контролю. У її склад входить керований РС сканер пучка, технологічні вимірювальні канали, а також набір робочих еталонів для калібрування каналів. Як інтерфейс використаний стандарт КАМАК. Програмне забезпечення комплексу дає можливість у режимі реального часу робити обробку інформації про параметри пучка, керувати ними, архивувати їх, а також обмінюватися інформацією в межах локальної технологічної мережі. Наявність бази даних «Замовник» з характеристиками продукції, що надходить, дозволяє оптимізувати режим її обробки методом комп'ютерного моделювання

The Kharkov X-ray Generator Facility NESTOR

WEPWA060 - ISBN 978-3-95450-122-9International audienceThe last few years the sources of the X-rays NESTOR based on a storage ring with low beam energy and Compton scattering of intense laser beam are under design and development in NSC KIPT. The main task of the project is to develop compact intense X-ray generator on the base of relatively cheap accelerator equipment and up-to-date laser technologies. The paper is devoted to description of the last results on construction and commissioning of the facility

Comprehensive viral oligonucleotide probe design using conserved protein regions

Oligonucleotide microarrays have been applied to microbial surveillance and discovery where highly multiplexed assays are required to address a wide range of genetic targets. Although printing density continues to increase, the design of comprehensive microbial probe sets remains a daunting challenge, particularly in virology where rapid sequence evolution and database expansion confound static solutions. Here, we present a strategy for probe design based on protein sequences that is responsive to the unique problems posed in virus detection and discovery. The method uses the Protein Families database (Pfam) and motif finding algorithms to identify oligonucleotide probes in conserved amino acid regions and untranslated sequences. In silico testing using an experimentally derived thermodynamic model indicated near complete coverage of the viral sequence database

Mechanism of Inhibition of Enveloped Virus Membrane Fusion by the Antiviral Drug Arbidol

The broad-spectrum antiviral arbidol (Arb) inhibits cell entry of enveloped viruses by blocking viral fusion with host cell membrane. To better understand Arb mechanism of action, we investigated its interactions with phospholipids and membrane peptides. We demonstrate that Arb associates with phospholipids in the micromolar range. NMR reveals that Arb interacts with the polar head-group of phospholipid at the membrane interface. Fluorescence studies of interactions between Arb and either tryptophan derivatives or membrane peptides reconstituted into liposomes show that Arb interacts with tryptophan in the micromolar range. Interestingly, apparent binding affinities between lipids and tryptophan residues are comparable with those of Arb IC50 of the hepatitis C virus (HCV) membrane fusion. Since tryptophan residues of membrane proteins are known to bind preferentially at the membrane interface, these data suggest that Arb could increase the strength of virus glycoprotein's interactions with the membrane, due to a dual binding mode involving aromatic residues and phospholipids. The resulting complexation would inhibit the expected viral glycoprotein conformational changes required during the fusion process. Our findings pave the way towards the design of new drugs exhibiting Arb-like interfacial membrane binding properties to inhibit early steps of virus entry, i.e., attractive targets to combat viral infection