55 research outputs found

    Coherent absorption and enhanced photoluminescence in thin layers of nanorods

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    We demonstrate a large light absorptance (80%) in a nanometric layer of quantum dots in rods (QRs) with a thickness of 23 nm. This behavior is explained in terms of the coherent absorption by interference of the light incident at a certain angle onto the very thin QR layer. We exploit this coherent light absorption to enhance the photoluminescent emission from the QRs. Up to a seven- and fivefold enhancement of the photoluminescence is observed for p- and s-polarized incident light, respectively.Comment: Physical Review B 201

    Interaction and coherence of a plasmon-exciton polariton condensate

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    Polaritons are quasiparticles arising from the strong coupling of electromagnetic waves in cavities and dipolar oscillations in a material medium. In this framework, localized surface plasmon in metallic nanoparticles defining optical nanocavities have attracted increasing interests in the last decade. This interest results from their sub-diffraction mode volume, which offers access to extremely high photonic densities by exploiting strong scattering cross-sections. However, high absorption losses in metals have hindered the observation of collective coherent phenomena, such as condensation. In this work we demonstrate the formation of a non-equilibrium room temperature plasmon-exciton-polariton condensate with a long range spatial coherence, extending a hundred of microns, well over the excitation area, by coupling Frenkel excitons in organic molecules to a multipolar mode in a lattice of plasmonic nanoparticles. Time-resolved experiments evidence the picosecond dynamics of the condensate and a sizeable blueshift, thus measuring for the first time the effect of polariton interactions in plasmonic cavities. Our results pave the way to the observation of room temperature superfluidity and novel nonlinear phenomena in plasmonic systems, challenging the common belief that absorption losses in metals prevent the realization of macroscopic quantum states.Comment: 23 pages, 5 figures, SI 7 pages, 5 figure

    Tailoring dispersion and eigenfield profiles of plasmonic surface lattice resonances

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    We investigate the radiative coupling between localized surface plasmon resonances (LSPRs) and Rayleigh anomalies (RAs) in periodic arrays of metallic nanorods with varying dimensions but equal lattice constants. The dimensions of the nanorods determine the energy and line width of the LSPR and, thus, enable tailoring of the mixed LSPR RA states: surface lattice resonances (SLRs). We present variable angle light extinction experimental spectra for five arrays with different nanorod width and explain our results with numerical simulations. The numerical simulations are done for driven and undriven systems, with the latter revealing the SLR eigenmode properties for the first time. We provide a plane wave model that interprets the near- and far-fields of these eigenmodes, describing the intricate behavior of confinement and radiative loss versus in-plane momentum. The SLR line width, band gap associated with the coupled modes, and field extension into the surrounding dielectric are tunable via the dimensions of the nanorods

    Giant optical birefringence of semiconductor nanowire metamaterials

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    Semiconductor nanowires exhibit large polarization anisotropy for the absorption and emission of light, making them ideal building blocks for novel photonic metamaterials. Here, we demonstrate that a high density of aligned nanowires exhibits giant optical birefringence, a collective phenomenon observable uniquely for collections of wires. The nanowire material was grown on gallium phosphide (GaP) (111) in the form of vertically standing GaP nanowires. We obtain the largest optical birefringence to date, with a difference between the in-plane and out-of-plane refractive indices of 0.80 and a relative birefringence of 43%. These values exceed by a factor of 75 the natural birefringence of quartz and a by more than a factor of two the highest values reported so far in other artificial materials. By exploiting the specific crystallographic growth directions of the nanowires on the substrate, we further demonstrate full control over the orientation of the optical birefringence effect in the metamaterial.Comment: 10 pages, 4 figure

    Plan de negocios para el desarrollo de un bar con espacios para romper objetos llamado Crash Bar

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    Al haber realizado el an?lisis de mercado en la categor?a de bares y centros de entretenimiento, se pudo evidenciar que actualmente no existe una propuesta diferenciadora que resalte sobre las dem?s; es as? que, nace la idea de negocio de implementar un bar con espacios para romper objetos llamado ?Crash Bar? dirigido a personas de los niveles socioecon?micos A y B de 20 a 35 a?os de edad de Lima Metropolitana, donde brindar experiencias ?nicas con el mejor servicio posible ser? la propuesta de valor. El plan de negocio fue desarrollado tomando fuentes primarias y secundarias, con el uso de investigaciones cuantitativas y cualitativas las cuales ayudaron a implementar un modelo acorde a los gustos y preferencias del p?blico objetivo

    Hybrid Semiconductor Nanowire-Metallic Yagi-Uda Antennas

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    We demonstrate the directional emission of individual GaAs nanowires by coupling this emission to Yagi-Uda optical antennas. In particular, we have replaced the resonant metallic feed element of the nanoantenna by an individual nanowire and measured with the microscope the photoluminescence of the hybrid structure as a function of the emission angle by imaging the back focal plane of the objective. The precise tuning of the dimensions of the metallic elements of the nanoantenna leads to a strong variation of the directionality of the emission, being able to change this emission from backward to forward. We explain the mechanism leading to this directional emission by finite difference time domain simulations of the scattering efficiency of the antenna elements. These results cast the first step toward the realization of electrically driven optical Yagi-Uda antenna emitters based on semiconductors nanowires

    Oil Price and Economic Growth: A Long Story?

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