1,721,107 research outputs found
Analysis of line shapes and strong coupling with intersubband transitions in one-dimensional metallodielectric photonic crystal slabs
No full textThis work reports a detailed study of quasi-guided mode resonances in metallodielectric photonic crystal slabs, focusing on the interaction with the intersubband transition supported by a multiple quantum well embedded in the photonic crystal itself. The strong light-matter coupling regime is obtained at room temperature in the mid-infrared spectral range, and its spectral fingerprints are analyzed in the framework of a Fano line-shape model. We propose an estimate of the light-matter coupling coefficient for arbitrarily shaped resonant cavities embedding multiple quantum wells supporting intersubband transitions, obtaining good agreement between theoretical calculations and experimental results
Microcavity polariton splitting of intersubband transitions
No full textThe optical response of the intersubband excitation of multiple two-dimensional electron gases within a semiconductor microcavity has been studied through angle-dependent reflectance measurements. Using a resonator based on total internal reflection, a clear splitting of about 14 meV of the coupled intersubband cavity modes is observed from 10 K to room temperature, with resulting polaritonlike dispersion. The experimental findings are in good agreement with theoretical calculations performed in a transfer-matrix formalism
III-V site-controlled quantum dots on Si patterned by nanoimprint lithography
No full textWe have successfully grown regular arrays of InAs/GaAs quantum dots on patterned Si substrates. Thanks to the capability of nanopimprint lithography, we were able to obtain uniform patterns extended over some cm2 areas, with periods of 300nm. Ex-situ and in-situ treatments of the surface allowed us to completely remove any residual oxides prior to growth without the use of hydrogen beams, at temperatures compatible with standard III-V molecular beam epitaxy. The growth protocol was optimized in order to obtain a perfect selectivity of InAs/GaAs nanostructures in the holes, without any deposition on the planar areas
Towards single-dot occupancy in directed self-assembly of InAs/GaAs quantum dots on nanoimprint lithography patterns
No full textMicrocavity polariton splitting of intersubband transitions
Full text linkThe optical response of the intersubband excitation of multiple two-dimensional electron gases within a semiconductor microcavity has been studied through angle-dependent reflectance measurements. Using a resonator based on total internal reflection, a clear splitting of about 14 meV of the coupled intersubband cavity modes is observed from 10 K to room temperature, with resulting polaritonlike dispersion. The experimental findings are in good agreement with theoretical calculations performed in a transfer-matrix formalism
One-dimensional surface-plasmon gratings for the excitation of intersubband polaritons in suspended membranes
No full textWe present the observation of the strong light-matter coupling regime between intersubband transitions of semiconductor quantum wells and the plasmonic-like resonances of a one dimensional metallic grating. Polariton spectra have been recorded in transmission employing a suspended membrane sample and are consistent with theoretical calculations. This arrangement, avoiding the complexity of dispersive substrate, is particularly attractive for the development of time-resolved pump-probe experiments. (C) 2011 Elsevier Ltd. All rights reserved
Metamaterial-enabled asymmetric negative refraction of GHz mechanical waves
Full text linkKnown examples of negative refraction in metamaterials do not distinguish between positive and negative angles of incidence. Here, the authors show that it is possible to break this symmetry using an asymmetric unit cell, and demonstrate it using a mechanical metamaterial working at GHz frequencies. Wave refraction at an interface between different materials is a basic yet fundamental phenomenon, transversal to several scientific realms - electromagnetism, gas and fluid acoustics, solid mechanics, and possibly also matter waves. Under specific circumstances, mostly enabled by structuration below the wavelength scale, i.e., through the metamaterial approach, waves undergo negative refraction, eventually enabling superlensing and transformation optics. However, presently known negative refraction systems are symmetric, in that they cannot distinguish between positive and negative angles of incidence. Exploiting a metamaterial with an asymmetric unit cell, we demonstrate that the aforementioned symmetry can be broken, ultimately relying on the specific shape of the Bloch mode isofrequency curves. Our study specialized upon a mechanical metamaterial operating at GHz frequency, which is by itself a building block for advanced technologies such as chip-scale hybrid optomechanical and electromechanical devices. However, the phenomenon is based on general wave theory concepts, and it applies to any frequency and time scale for any kind of linear waves, provided that a suitable shaping of the isofrequency contours is implemented
Interedge strong-to-weak scattering evolution at a constriction in the fractional quantum Hall regime
No full textControlling polariton coupling in intersubband microcavities
No full textWe report the external control of the intersubband polariton coupling by manipulating the carrier density in quantum wells resonantly coupled to a GaAs/AlGaAs microcavity. The electrons in the wells were tuned by means of a depletion gate Was or by utilizing charge transfer between the energetically aligned ground subbands of asymmetric tunnel-coupled quantum wells. We propose the use of tunnel-assisted control of the polariton ground state in an asymmetrically coupled quantum well for implementing ultrafast modulation of intersubband polaritons
Gestión integrada de la inocuidad en dietas especiales listas para el consumo
Full text linkFil: Maggi, M. L. Gobierno de la Provincia de Córdoba. CEPROCOR; Argentina.Fil: Maino, A. Planta elaboradora de alimentos; Argentina.Fil: Biasiol, G. Planta elaboradora de alimentos; Argentina.Fil: Maggi, L. Planta elaboradora de alimentos; Argentina.Fil: Lopez, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Ciencia y Tecnología de los Alimentos; Argentina.El Análisis de Peligros y Puntos Críticos de Control (HACCP) constituye un marco fundamental
para una gestión eficaz de la inocuidad de los alimentos siendo la herramienta más segura a la
hora de integrar estos avances a los sistemas de control de la industria. En la ciudad de
Córdoba, existen programas alimentarios gubernamentales provistos por empresas privadas,
que contemplan beneficiarios con determinadas patologías a los cuales se les brindan variantes
del régimen normal o dietas especiales listas para el consumo. Considerando el grupo etario, su
nivel social y sabiendo que tienen una menor resistencia a las enfermedades resulta de vital
importancia asegurar la inocuidad de estos alimentos, siendo la aplicación de la secuencia lógica
del sistema HACCP particularmente relevante en la vigilancia de los mismos.www.inv.icta.efn.uncor.edu/?page_id=145Fil: Maggi, M. L. Gobierno de la Provincia de Córdoba. CEPROCOR; Argentina.Fil: Maino, A. Planta elaboradora de alimentos; Argentina.Fil: Biasiol, G. Planta elaboradora de alimentos; Argentina.Fil: Maggi, L. Planta elaboradora de alimentos; Argentina.Fil: Lopez, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Instituto de Ciencia y Tecnología de los Alimentos; Argentina.Otras Ingeniería Químic
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