Transformation Optics Approach to Plasmon-Exciton Strong Coupling in Nanocavities

We investigate the conditions yielding plasmon-exciton strong coupling at the single emitter level in the gap between two metal nanoparticles. A quasi-analytical transformation optics approach is developed that makes possible a thorough exploration of this hybrid system incorporating the full richness of its plasmonic spectrum. This allows us to reveal that by placing the emitter away from the cavity center, its coupling to multipolar dark modes of both even and odd parity increases remarkably. This way, reversible dynamics in the population of the quantum emitter takes place in feasible implementations of this archetypal nanocavity.Comment: 5 pages, 4 figure

High-order localized spoof surface plasmon resonances and experimental verifications

We theoretically demonstrated and experimentally verified high-order radial spoof localized surface plasmon resonances supported by textured metal particles. Through an effective medium theory and exact numerical simulations, we show the emergence of these geometrically-originated electromagnetic modes at microwave frequencies. The occurrence of high-order radial spoof plasmon resonances is experimentally verified in ultrathin disks. Their spectral and near-field properties are characterized experimentally, showing an excellent agreement with theoretical predictions. Our findings shed light into the nature of spoof localized surface plasmons, and open the way to the design of broadband plasmonic devices able to operate at very different frequency regimes.Comment: 29 pages, 10 figure

Obtención de gas de síntesis por tratamiento térmico en microondas de biomasa y biogás

En este trabajo se estudia la pirólisis, tanto en microondas como en horno eléctrico, de un residuo procedente de la industria del café, con objeto de comparar la influencia del calentamiento en las características de las fracciones resultantes. La alta proporción de gas de síntesis (H2 + CO) obtenida con el microondas (hasta del 73%) es debida al hecho que la auto-gasificación del carbonizado con el CO2 liberado y que la descomposición catalítica de CH4 se ven favorecidas por este tipo de calentamiento.Así, los experimentos de estas dos últimas reacciones llevadas a cabo de manera individual, con ambos sistemas de calentamiento, demuestran que se dan mayores conversiones en el microondas. En el caso de la descomposición de CH4, la conversión, que inicialmente alcanza valores próximos al 100%, experimentaun descenso importante al cabo de pocos minutos como consecuencia de la formación de depósitos de carbono que bloquean los centros activos de la superficie del catalizador. Sin embargo, una combinación de ambas reacciones, i.e. reformado de CH4 con CO2, mejora el proceso de conversión de CH4 a H2, debido a que el CO2 gasifica los depósitos de carbono generados, permitiendo una regeneración “in situ” del catalizador. Estos resultados han servido como punto de partida para el desarrollo de un nuevo procedimiento que permitiría convertir biogás en gas de síntesis

Physical and Excess Properties for Binary Systems Containing an Alcohol and Ionic Liquid at T = 298.15K

AbstractIn this paper, density, speed of sound and refractive index of six binary systems (alcohol + ionic liquid) were measured, along the whole composition range, at T = 298.15K and atmospheric pressure. The ionic liquids used in this work are constituted by different cations (pyridinium and pyrrolidinium), anions (trifluoromethanesulfonate and dicyanamide) and alkyl-side chain (propyl- and butyl-). From the experimental data, excess molar volumes, excess molar isentropic compressions and excess refractive index were calculated and satisfactorily fitted using the Redlich-Kister equation. The obtained results show that the physical and excess properties studied in this work are dependent on the structure of the ILs, especially on the anion

Anomalous spin textures in a 2D topological superconductor induced by point impurities

Topological superconductors are foreseen as good candidates for the search of Majorana zero modes, where they appear as edge states and can be used for quantum computation. In this context, it becomes necessary to study the robustness and behavior of electron states in topological superconductors when a magnetic or non-magnetic impurity is present. We focus on scattering resonances in the bands and on spin texture to know what the spin behavior of the electrons in the system will be. We find that the scattering resonances appear outside the superconducting gap, thus providing evidence of topological robustness. We also find non-trivial and anisotropic spin textures related to the Dzyaloshinskii-Moriya interaction. The spin textures show a Ruderman-Kittel-Kasuya-Yosida interaction governed by Friedel oscillations. We believe that our results are useful for further studies which consider many-point-impurity scattering or a more structured impurity potential with a finite range