Optimal control of electromagnetic field using metallic nanoclusters

The dielectric properties of metallic nanoclusters in the presence of an applied electromagnetic field are investigated using non-local linear response theory. In the quantum limit we find a non-trivial dependence of the induced field and charge distribution on the spatial separation between the clusters and on the frequency of the driving field. Using a genetic algorithm, these quantum functionalities are exploited to custom-design sub-wavelength lenses with a frequency controlled switching capability.Comment: accepted for publication in New Journal of Physic

Mechanics and Mathematical Modeling of Class III Treatment with Orthodontic Appliances with a Movable Ramp

Treatment of class III is a current problem in orthodontics that requires constant improvement of its methods, development of new or modifications of known methods and techniques. We have developed and studied the modification of removable functionally-directing orthodontic appliances for treatment of Class III, which consists of a plastic base, vestibular arc, retaining clasps, ramp, which is connected with the base by means of two torsion springs. Its usage ensures a prolonged contact of ramp with the teeth. We studied two types of club-shaped springs (torsion springs): one spring, which create an amortization effect during the action of the ramp, but do not change its inclination angle and second one – spring that seek to increase the angle of the ramp inclination due to the disclosure of its curl

Long-range and rapid transport of individual nano-objects by a hybrid electrothermoplasmonic nanotweezer

Plasmon-enhanced optical trapping is being actively studied to provide efficient manipulation of nanometre-sized objects. However, a long-standing issue with previously proposed solutions is how to controllably load the trap on-demand without relying on Brownian diffusion. Here, we show that the photo-induced heating of a nanoantenna in conjunction with an applied a.c. electric field can initiate rapid microscale fluid motion and particle transport with a velocity exceeding 10 μm s -1 , which is over two orders of magnitude faster than previously predicted. Our electrothermoplasmonic device enables on-demand long-range and rapid delivery of single nano-objects to specific plasmonic nanoantennas, where they can be trapped and even locked in place. We also present a physical model that elucidates the role of both heat-induced fluidic motion and plasmonic field enhancement in the plasmon-assisted optical trapping process. Finally, by applying a d.c. field or low-frequency a.c. field (below 10 Hz) while the particle is held in the trap by the gradient force, the trapped nano-objects can be immobilized into plasmonic hotspots, thereby providing the potential for effective low-power nanomanufacturing on-chip

Science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems

We present the science and technology roadmap for graphene, related two-dimensional crystals, and hybrid systems, targeting an evolution in technology, that might lead to impacts and benefits reaching into most areas of society. This roadmap was developed within the framework of the European Graphene Flagship and outlines the main targets and research areas as best understood at the start of this ambitious project. We provide an overview of the key aspects of graphene and related materials (GRMs), ranging from fundamental research challenges to a variety of applications in a large number of sectors, highlighting the steps necessary to take GRMs from a state of raw potential to a point where they might revolutionize multiple industries. We also define an extensive list of acronyms in an effort to standardize the nomenclature in this emerging field.Peer ReviewedPostprint (published version

Non-polaritonic effects in cavity-modified photochemistry

Strong coupling of molecules to vacuum fields has been widely reported to lead to modified chemical properties such as reaction rates. However, some recent attempts to reproduce infrared strong coupling results have not been successful, suggesting that factors other than strong coupling may sometimes be involved. Here we re-examine the first of these vacuum-modified chemistry experiments, in which changes to a molecular photoisomerisation process were attributed to strong coupling of the molecules to visible light. We observed significant variations in photoisomerisation rates for molecules placed in a variety of optical cavity structures, but found no evidence that these changes need to be attributed to strong coupling. Instead, we suggest that the photoisomerisation rates involved are most strongly influenced by the absorption of ultraviolet radiation in the cavity. Our results indicate that care must be taken to rule out non-polaritonic effects before invoking strong coupling to explain any changes of chemical properties arising in cavity-based experiments.Comment: 31 pages, 16 figure

STUDY OF ANTI-OSTEOPOROTIC ACTION OF DRUGS FROM THE GROUP OF STATINS

In an experiment on female Wistar white rats, the osteoprotective effect of atorvastatin, simvastatin and rosuvastatin was studied in a model of experimental osteoporosis caused by bilateral ovariectomy. It was found that after ovariectomy in female rats develops endothelial dysfunction, including the vessels of the microcirculatory of the bone, leading to a deterioration of blood supply to bone tissue and the occurrence of osteoporosis. It was found that atorvastatin, simvastatin and rosuvastatin, possessing endothelioprotective activity, prevent deterioration of blood supply to bone tissue and thinning of bone trabeculae, thus having anti-osteoporotic activity. Key words: osteoporosis, endothelial dysfunction, statins, atorvastatin, simvastatin, rosuvastatin, strontium ranelate

Nanoscale light field imaging with graphene

Modern nano-optics and nanophotonics rely heavily on the precise formation of nanostructured light fields. Accurate and deterministic light field formation and characterization are indispensable for device operation as well as for revealing the underlying physical mechanisms involved. Despite a significant progress made in detection of scattered light with extremely high precision down to 1 nm resolution, there are only a limited number of techniques for direct subwavelength light mapping which do not rely on measurements of light scattering, fluorescence, or non-linear light conversion. Hence, techniques for direct conversion of light to electrical signals with precise and non-destructive imaging of nanoscale light would be of great benefit. Here, we report a nanoscale light field imaging approach based on photodetection with a p-n junction that is induced and moved inside a graphene probe by gate voltage, formed by a set of external electrodes. The spatial resolution of this electrical scanning technique is determined by p-n junction width, reaching ~ 20 nm. The developed approach is demonstrated with mapping the electric field distribution of a plasmonic slot-waveguide at telecom wavelengths. Our method provides a non-invasive nanoscale light field imaging that ensures extremely high spatial resolution and precision.</p

IN MEMORY OF ARKADY VIKTOROVICH KRYAZHIMSKIY (1949–2014)

The article is devoted to the description of Academician Arkady Kryazhimskiy's life path. The facts of the scientific biography of Acad. Kryazhimskiy are presented with the emphasis on his outstanding contribution into the theory of dynamic inversion, the theory of differential games, and control theory. His personal talents in different spheres are also marked out

IN MEMORY OF ARKADY VIKTOROVICH KRYAZHIMSKIY (1949–2014)

The article is devoted to the description of Academician Arkady Kryazhimskiy's life path. The facts of the scientific biography of Acad. Kryazhimskiy are presented with the emphasis on his outstanding contribution into the theory of dynamic inversion, the theory of differential games, and control theory. His personal talents in different spheres are also marked out