Waveguide coupling gratings for high-sensitivity biochemical sensors

Grating coupling is now currently used in evanescent-wave biochemical sensors as a waveguide coupling element or as the sensing element. In most coupling cases of practical interest, the Rayleigh-Fourier method is valid, and leads to physically meaningful analytical solutions allowing grating coupling to be designed in simple terms. In the present paper the emphasis is placed on the grating as a waveguide coupling element

Effect of substrate proximity on luminescence yield from Si nanocrystals

The influence of the proximity of a high refractive index substrate on the luminescence of Si nanocrystals was investigated by time-integrated and time-resolved photoluminescence. The luminescence yield was found to be ∼2.5 times larger for emitters distanced from the substrate compared to those in proximity with the substrate, while luminescence decay measurements revealed only a slight increase in the luminescence lifetime (∼15%). Results are discussed in terms of local density of optical modes surrounding a pointlike light emitter with important implications for the collection efficiency of luminescence and the estimation of internal quantum efficiency for a quantum dot.Support for this work was provided by the Swedish Research Council VR and the Australian Research Council ARC

Enhancement of optical switching parameter and third-order optical nonlinearities in embedded Si nanocrystals: a theoretical assessment

Third-order bound-charge electronic nonlinearities of Si nanocrystals (NCs) embedded in a wide band-gap matrix representing silica are theoretically studied using an atomistic pseudopotential approach. Nonlinear refractive index, two-photon absorption and optical switching parameter are examined from small clusters to NCs up to a size of 3 nm. Compared to bulk values, Si NCs show higher third-order optical nonlinearities and much wider two-photon absorption threshold which gives rise to enhancement in the optical switching parameter.Comment: 8 pages, 3 figures, to be published in Optics Communication

Creative laboratory works on disciplene «Microwaves and antennas»

Представлены лабораторные работы по высокочастотной схемотехнике «Проектирование полосно-пропускающего микрополоскового фильтра» и «Согласование нагрузки с линией питания» дисциплины «Устройства СВЧ и антенны» направления подготовки «Радиотехника». Методика выполнения работ предусматривает расчет, изготовление и измерение характеристик разработанных устройств.Laboratory works on microwave design discipline "Microwaves and antennas" devoted to the analysis of microstrip filters and matching are presented. The technique of suggested works is based on microwave calculations, design and measurement of characteristics of developed devices

Tiling large areas with luminescent solar concentrators: geometry effects

Luminescence solar concentrators act as semi-transparent photovoltaic cells and can be applied to large surface areas in modern urban environment. In this paper their optical efficiencies were analytically derived for different unit shapes as simple, integral-free expressions. Perimeter length increase for the same enclosed area requires more photodetectors, yet reduces optical losses per unit. An exact interplay between these two parameters is presented, which can be directly applied to the analysis of tiling for large areas. An explicit expression for the critical size of an LSC unit, above which its inner part becomes inactive, has been obtained. Fabrication of devices larger than specified by this limit should be discouraged from efficiency considerations.Comment: 12 pages, 5 figure

Reciprocity Violation for Mie Scatterers at the Interface and a Scattering Solar Concentrator

It is shown that reciprocity of the optical path can be violated through asymmetric strength coupling via near-field from resonant Mie scatterers to total internal reflection modes in a dielectric slab. Numerical simulations for silicon nanospheres separated by a nanogap from the glass substrate reveal that at least two orders of magnitude rectification ratio can be realized for such an optical diode configuration. Implementation to a solar light harvesting device, a scattering solar concentrator, is discussed, indicating a similar efficiency is achievable as for the state-of-the-art devices based on luminescence.Comment: 4 pages, 4 figure

CdSe/CdS dot-in-rods nanocrystals fast blinking dynamics

The blinking dynamics of colloidal core-shell CdSe/CdS dot-in-rods is studied in detail at the single particle level. Analyzing the autocorrelation function of the fluorescence intensity, we demonstrate that these nanoemitters are characterized by a short value of the mean duration of bright periods (ten to a few hundreds of microseconds). The comparison of the results obtained for samples with different geometries shows that not only the shell thickness is crucial but also the shape of the dot- in-rods. Increasing the shell aspect ratio results in shorter bright periods suggesting that surface traps impact the stability of the fluorescence intensity

NHERITANCE OF CRYPTOCURRENCY AND DIGITAL INVENTORY IN MULTIPLAYER GAMES

The article discusses the possibility of inheriting cryptocurrencies and digital inventory in multiplayer games. The relevance of the topic is reflected in the problems existing both in theory and in practice, namely: the absence of a legal definition of cryptocurrency in Russian legislation; the problem of the legal nature of in-game inventory items; the lack of legal regulation of Internet accounts from the standpoint of hereditary legal relations. The analysis and comparison of the norms of foreign legislation of a number of countries (USA, Taiwan) is carried out within the framework of the institute under consideration. The purpose of this work is to study the norms of domestic legislation, theoretical foundations and law enforcement practice, which are aimed at the formation and regulation of the institute of inheritance of «digital property», as well as the analysis of foreign legislation to establish the possibility of convergence of the norms governing specified objects. In order to achieve the above-mentioned goal, the following tasks were identified, namely: analysis of Russian legislation in order to identify problems in the regulation of the institution in question; analysis of the norms of foreign legislation regulating this institution; analysis of gaps related to the legal regulation of inheritance of cryptocurrencies and digital inventory in multiplayer games in the Civil Code of the Russian Federation. The methodology of this research includes private and general scientific research methods, namely analysis, synthesis, deduction, induction, comparative legal method. In conclusion, proposals were made to improve the norms of civil legislation concerning the inheritance of cryptocurrencies and digital inventory in multiplayer games