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Sepulveda B.,CIBER ISCIII | Gonzalez-Diaz J.B.,Imm Institute Microelectronica Of Madrid Cnm Csic | Garcia-Martin A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Lechuga L.M.,CIBER ISCIII | Armelles G.,Imm Institute Microelectronica Of Madrid Cnm Csic
Physical Review Letters | Year: 2010

In this Letter we show that nanostructures made out of pure noble metals can exhibit measurable magneto-optic activity at low magnetic fields. This phenomenon occurs when the localized surface plasmon resonance of the nanostructure is excited in the presence of a static magnetic field parallel to the propagation of incident light. The large magneto-optical response observed comes from an increase of the magnetic Lorentz force induced by the large collective movement of the conduction electrons in the nanostructures when the resonance is excited. © 2010 The American Physical Society.


Garcia-Martin A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Ward D.R.,Rice University | Natelson D.,Rice University | Cuevas J.C.,Autonomous University of Madrid
Physical Review B - Condensed Matter and Materials Physics | Year: 2011

Motivated by recent experiments, we present here a theoretical analysis of the optical response of sharp gold electrodes separated by a subnanometer gap. In particular, we have used classical finite difference time domain simulations to investigate the electric-field distribution in these nanojunctions upon illumination. Our results show a strong confinement of the field within the gap region, resulting in a large enhancement compared to the incident field. Enhancement factors exceeding 103 are found for interelectrode distances on the order of a few angstrom, which are fully compatible with the experimental findings. Such huge enhancements originate from the coupling of the incident light to the evanescent field of hybrid plasmons involving charge density oscillations in both electrodes. © 2011 American Physical Society.


Gonzalez-Diaz J.B.,Imm Institute Microelectronica Of Madrid Cnm Csic | Sepulveda B.,CIBER ISCIII | Garcia-Martin A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Armelles G.,Imm Institute Microelectronica Of Madrid Cnm Csic
Applied Physics Letters | Year: 2010

In this work, we study the plasmon-mediated enhancement of the magneto-optical (MO) activity in the case of Au/Co/Au nanodisks as a function of the Co content. We show that both the spectral shape and amplitude of the complex polar Kerr rotation are modified by the relative amount of gold (diamagnetic) and cobalt (ferromagnetic). We demonstrate that such shape modification is dictated by the predominance of the absorptive or dispersive part of the MO constant in each material, which is intimately related to the origin of their MO activity. © 2010 American Institute of Physics.


Caballero B.,Imm Institute Microelectronica Of Madrid Cnm Csic | Caballero B.,Autonomous University of Madrid | Garcia-Martin A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Cuevas J.C.,Autonomous University of Madrid
Optics Express | Year: 2015

We present a theoretical study of the Faraday effect in hybrid magneto-plasmonic crystals that consist of Au-Co-Au perforated membranes with a periodic array of sub-wavelength holes. We show that in these hybrid systems the interplay between the extraordinary optical transmission and the magneto-optical activity leads to a resonant enhancement of the Faraday rotation, as compared to purely ferromagnetic membranes. In particular, we determine the geometrical parameters for which this enhancement is optimized and show that the inclusion of a noble metal like Au dramatically increases the Faraday rotation over a broad bandwidth. Moreover, we show that the analysis of the Faraday rotation in these periodically perforated membranes provides a further insight into the origin of the extraordinary optical transmission. © 2015 Optical Society of America.


Vitrey A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Aigouy L.,CNRS Physics and Materials Study Laboratory | Prieto P.,Imm Institute Microelectronica Of Madrid Cnm Csic | Garcia-Martin J.M.,Imm Institute Microelectronica Of Madrid Cnm Csic | Gonzalez M.U.,Imm Institute Microelectronica Of Madrid Cnm Csic
Nano Letters | Year: 2014

In this work we discuss the excitation of parallel collective resonances in arrays of gold nanoparticles. Parallel collective resonances result from the coupling of the nanoparticles localized surface plasmons with diffraction orders traveling in the direction parallel to the polarization vector. While they provide field enhancement and delocalization as the standard collective resonances, our results suggest that parallel resonances could exhibit greater tolerance to index asymmetry in the environment surrounding the arrays. The near- and far-field properties of these resonances are analyzed, both experimentally and numerically. © 2014 American Chemical Society.


Manzano C.V.,Imm Institute Microelectronica Of Madrid Cnm Csic | Martin J.,Imm Institute Microelectronica Of Madrid Cnm Csic | Martin-Gonzalez M.S.,Imm Institute Microelectronica Of Madrid Cnm Csic
Microporous and Mesoporous Materials | Year: 2014

Ordered anodic aluminum oxide (AAO) templates with pores of 12 nm in diameter and aspect-ratios (length-to-diameter) of >1000 are prepared by a simple two-step anodization process under mild-anodization conditions. Such a low diameter pores are consequence of the reduction of the dielectric constant of the electrolyte together with the effect of increasing the electrolyte viscosity. We show that the temperature has a strong impact on reducing the pore diameter, as provokes the increase of viscosity of the medium and thus the hindering of the diffusion of species involved in the widening of pores. Moreover, we manage to stop the AAO growth process at the pore nucleation stage and we show that 8 nm in diameter pores are originally formed under these conditions. The presented ultra-narrow pore templates may allow for the preparation of ordered arrays of high aspect-ratio ultra-small one dimensional (1D) nanostructures that could be useful to explore quantum phenomena and integrate quantum-devices. © 2013 Elsevier Inc. All rights reserved.


Martin J.,Imm Institute Microelectronica Of Madrid Cnm Csic | Manzano C.V.,Imm Institute Microelectronica Of Madrid Cnm Csic | Martin-Gonzalez M.,Imm Institute Microelectronica Of Madrid Cnm Csic
Microporous and Mesoporous Materials | Year: 2012

The growth of self-ordered anodic aluminum oxide (AAO) templates with pore diameters in the 140-400 nm range is achieved by anodization in phosphoric acid at low temperatures (-4 °C). The procedure used in this study is able to completely avoid the "burning" of the oxide, highly frequent in anodizations in phosphoric acid solutions at high voltages. The current density measured during the anodizations is rather low, 0.6-0.7 mA/cm 2; therefore, low growth rates have been also measured (<2 μm/h). AAO templates present a relatively low porosity value of 8.4%. However, a considerable pore-enlargement-rate (v Δd = 0.636 ± 0.101 nm/h) has been observed as a consequence of the chemical dissolution of the pore walls during the anodization. Thus, the results reported here constitute an exhaustive study on the preparation of large-diameter-pore self-ordered AAO templates that enables both to access to pore diameters up to now inaccessible and to efficiently overcome the difficulties of their fabrication process ascribed to its aggressive reaction conditions. © 2011 Elsevier Inc. All rights reserved.


Armelles G.,Imm Institute Microelectronica Of Madrid Cnm Csic | Dmitriev A.,Chalmers University of Technology
New Journal of Physics | Year: 2014

In this 'focus on' collection, a snapshot of the new, fast emerging field of magnetoplasmonics is presented. The research in the field deals with the combination of plasmonics and magnetism to elucidate the fundamentals of spin - plasmon interactions and reach new functionalities such as the enhancement of magneto-optical activity in various materials, active control of plasmons with weak magnetic fields, magnetoplasmonics-based bio- and chemical sensing, magnetophotonic and magnetoplasmonic crystals as modulators of light transmission and reflection, and many others. © 2014 IOP Publishing Ltd and Deutsche Physikalische Gesellschaft.


Ferreiro-Vila E.,Imm Institute Microelectronica Of Madrid Cnm Csic | Garcia-Martin J.M.,Imm Institute Microelectronica Of Madrid Cnm Csic | Cebollada A.,Imm Institute Microelectronica Of Madrid Cnm Csic | Gonzalez M.U.,Imm Institute Microelectronica Of Madrid Cnm Csic
Optics Express | Year: 2013

The magnetic modulation of the surface plasmon-polariton (SPP) wavevector is experimentally and theoretically studied for the plasmonic modes excited in metal-insulator-metal (MIM) magnetoplasmonic cavities. For this purpose, Ag/SiO2/Ag multilayers with different SiO2 layer thickness in which a thin Co layer is positioned near the top Ag/SiO2 interface, near the bottom SiO2/Ag one, or near both of them, are studied. The magnetoplasmonic MIM cavities present symmetric (SM) and antisymmetric (AM) plasmonic modes, of different wavevector and electromagnetic field profiles inside the MIM cavity. We show that the magnetic SPP wavevector modulation strongly depends on which mode is considered, the cavity thickness, and the number and specific location of Co layers within the structure. With only one ferromagnetic layer, a net modulation is obtained, of higher magnitude as we reduce the SiO2 layer thickness. The introduction of a second Co layer in the structure reduces the modulation due to the non-reciprocal character of SPP modes under an applied magnetic field. Moreover, we demonstrate that the non-reciprocal nature of the SPP modulation can be experimentally visualized in the magnetic hysteresis loops under plasmon excitation conditions by using two Co layers with different magnetization switching fields. © 2013 Optical Society of America.


Banthi J.C.,Imm Institute Microelectronica Of Madrid Cnm Csic | Meneses-Rodriguez D.,Imm Institute Microelectronica Of Madrid Cnm Csic | Garcia F.,Imm Institute Microelectronica Of Madrid Cnm Csic | Gonzalez M.U.,Imm Institute Microelectronica Of Madrid Cnm Csic | And 3 more authors.
Advanced Materials | Year: 2012

Metal-dielectric Au-Co-SiO 2 magnetoplasmonic nanodisks are found to exhibit large magneto-optical activity and low optical losses. The internal architecture of the nanodisks is such that, in resonant conditions, the electromagnetic field undertakes a particular spatial distribution. This makes it possible to maximize the electromagnetic field at the magneto-optically active layers and minimize it in the other, optically lossy ones. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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