85 research outputs found

    Total Polarisation Conversion in Two-dimensional Electron System under Cyclotron Resonance Conditions

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    The polarisation conversion of a linear polarised electromagnetic wave incident onto a two-dimensional (2D) electron system at an angle is theoretically studied. We consider the 2D system located at the interface between two dielectric media with different dielectric constants. An external dc magnetic field is assumed to be directed along the normal to the 2D electron layer. In such a configuration the cyclotron-polaritons (CPs) in 2D electron system can be excited with the frequencies in the vicinity of the cyclotron frequency. Under the CPs excitation the resonance polarisation conversion of electromagnetic wave greatly increases in the system. In the absence of the electron scattering in 2D system, the polarisation conversion reaches 100% at a certain value of the angle of incidence which is more than the total reflection angle. Extremely high polarisation conversion takes place in a quite wide range of variation of the angle of incidence. High polarisation conversion efficiency (above 80%) remains when the actual electron scattering in the 2D system on GsAs is taken into account. The considered phenomena may be taken up in polarisation spectroscopy of 2D electron systems.Comment: 7 pages, 5 Postscript figure

    Tunable Plasmon Molecules in Overlapping Nanovoids

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    Coupled and shape-tailored metallic nanoparticles are known to exhibit hybridized plasmon resonances. This Letter discuss the optical properties of a complementary system formed by overlapped nanovoid dimers buried in gold and filled with silica. This is an alternative route for plasmon engineering that benefits from vanishing radiation losses. Our analysis demonstrates the possibility of designing artificial plasmon molecules on the basis of void plasmon hybridization, which allows fine mode tuning by varying the overlap between voids. The proposed structures could find application to both signal processing through buried optical elements and tunable-plasmon biosensing.Comment: 4 pages, 4 figure

    Graphene plasmonics: A platform for strong light-matter interaction

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    Graphene plasmons provide a suitable alternative to noble-metal plasmons because they exhibit much larger confinement and relatively long propagation distances, with the advantage of being highly tunable via electrostatic gating. We report strong light- matter interaction assisted by graphene plasmons, and in particular, we predict unprecedented high decay rates of quantum emitters in the proximity of a carbon sheet, large vacuum Rabi splitting and Purcell factors, and extinction cross sections exceeding the geometrical area in graphene ribbons and nanometer-sized disks. Our results provide the basis for the emerging and potentially far-reaching field of graphene plasmonics, offering an ideal platform for cavity quantum electrodynamics and supporting the possibility of single-molecule, single-plasmon devices.Comment: 39 pages, 15 figure

    Age and gender peculiarities of hysterical neurotic psychopathology

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    The purpose of research was definition of psychopathological peculiarities of hysterical neurotic disorders and to reveal influence of age and gender factors. We investigated 109 patients. There were 62 patients in the basic group (23 of them were men and 39 of them were women) at the age from 45 to 63 and 47 patient in the control group (19 of them were men and 28 were women) at the age from 18 to 44. It is established that old age is characterized in anxious depression with egocentric orientation, shocking blackmailing destructive aggressive infantile behavior, substantial dimorphism of conversion displays, somatophorms disorders of women and obsessive compulsive disorders of men.Цель работы: с целью определения психопатологических особенностей истерических невротических расстройств у больных с учётом патоформирующего влияния возрастного и гендерного факторов обследовано 109 пациентов: 62 пациента (23 мужчины и 39 женщин) в возрасте от 45 до 63 лет составили основную группу, 47 пациентов (19 мужчин и 28 женщин) в возрасте от 18 до 44 лет - контрольную. Установлено, что истерическому неврозу в позднем возрасте свойственна тревожная депрессия с эгоцентрической направленностью, эпатажно-шантажным деструктивно-агрессивным инфантильным поведением, содержательным диморфизмом конверсионных проявлений, соматоформными расстройствами у женщин и обсессивно-компульсивными расстройствами - у мужчин

    Anisotropy effects on the plasmonic response of nanoparticle dimers

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    We present an ab initio study of the anisotropy and atomic relaxation effects on the optical properties of nanoparticle dimers. Special emphasis is placed on the hybridization process of localized surface plasmons, plasmon-mediated photoinduced currents, and electric-field enhancement in the dimer junction. We show that there is a critical range of separations between the clusters (0.1–0.5 nm) in which the detailed atomic structure in the junction and the relative orientation of the nanoparticles have to be considered to obtain quantitative predictions for realistic nanoplasmonic devices. It is worth noting that this regime is characterized by the emergence of electron tunneling as a response to the driven electromagnetic field. The orientation of the particles not only modifies the attainable electric field enhancement but can lead to qualitative changes in the optical absorption spectrum of the system.We thankfully acknowledge financial support by the European Research Council (ERC-2010-AdG Proposal No. 267374 and ERC-2011-AdG Proposal No. 290891), the Spanish Government (Grants MAT2011-28581-C02-01, FIS2013-46159-C3-1-P, and MAT2014-53432-C5-5-R), and the Basque Country Government (Grupos Consolidados IT-578-13).Peer Reviewe

    Quantum surface-response of metals revealed by acoustic graphene plasmons

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    A quantitative understanding of the electromagnetic response of materials is essential for the precise engineering of maximal, versatile, and controllable light-matter interactions. Material surfaces, in particular, are prominent platforms for enhancing electromagnetic interactions and for tailoring chemical processes. However, at the deep nanoscale, the electromagnetic response of electron systems is significantly impacted by quantum surface-response at material interfaces, which is challenging to probe using standard optical techniques. Here, we show how ultraconfined acoustic graphene plasmons in graphene-dielectric-metal structures can be used to probe the quantum surface-response functions of nearby metals, here encoded through the so-called Feibelman d-parameters. Based on our theoretical formalism, we introduce a concrete proposal for experimentally inferring the low-frequency quantum response of metals from quantum shifts of the acoustic graphene plasmons dispersion, and demonstrate that the high field confinement of acoustic graphene plasmons can resolve intrinsically quantum mechanical electronic length-scales with subnanometer resolution. Our findings reveal a promising scheme to probe the quantum response of metals, and further suggest the utilization of acoustic graphene plasmons as plasmon rulers with angstrom-scale accuracy. Knowledge of the quantum response of materials is essential for designing light-matter interactions at the nanoscale. Here, the authors report a theory for understanding the impact of metallic quantum response on acoustic graphene plasmons and how such response could be inferred from measurements.N.A.M. is a VILLUM Investigator supported by VILLUM FONDEN (Grant No. 16498) and Independent Research Fund Denmark (Grant No. 7026-00117B). The Center for Nano Optics is financially supported by the University of Southern Denmark (SDU 2020 funding). The Center for Nanostructured Graphene (CNG) is sponsored by the Danish National Research Foundation (Project No. DNRF103). This work was partly supported by the Army Research Office through the Institute for Soldier Nanotechnologies under Contract No. W911NF-18-2-0048. N.M.R.P. acknowledges support from the European Commission through the project "Graphene-Driven Revolutions in ICT and Beyond" (No. 881603, Core 3), COMPETE 2020, PORTUGAL 2020, FEDER and the Portuguese Foundation for Science and Technology (FCT) through project POCI-01-0145-FEDER028114 and through the framework of the Strategic Financing UID/FIS/04650/2019. F.H. L.K. acknowledges financial support from the Government of Catalonia through the SGR grant and from the Spanish Ministry of Economy and Competitiveness (MINECO) through the Severo Ochoa Programme for Centres of Excellence in R&D (SEV-20150522), support by Fundacio Cellex Barcelona, Generalitat de Catalunya through the CERCA program, and the MINECO grants Plan Nacional (FIS2016-81044-P) and the Agency for Management of University and Research Grants (AGAUR) 2017 SGR 1656. Furthermore, the research leading to these results has received funding from the European Union's Horizon 2020 program under the Graphene Flagship Grant Agreements No. 785219 (Core 2) and no. 881603 (Core 3), and the Quantum Flagship Grant No. 820378. This work was also supported by the ERC TOPONANOP (Grant No. 726001)

    Active liquid crystal tuning of metallic nanoantenna enhanced light emission from colloidal quantum dots

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    A system comprising an aluminum nanoantenna array on top of a luminescent colloidal quantum dot waveguide and covered by a thermotropic liquid crystal (LC) is introduced. By heating the LC above its critical temperature, we demonstrate that the concomitant refractive index change modifies the hybrid plasmonic-photonic resonances in the system. This enables active control of the spectrum and directionality of the narrow-band (similar to 6 nm) enhancement of quantum dot photoluminescence by the metallic nanoantennas

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