Light scattering by a magneto-optical nanoparticle in front of a flat surface: Perturbative approach

We develop a perturbative formalism for the interaction of a magneto-optical nanoparticle with a flat surface made of a dielectric or metallic material. The formalism leads to a simple interpretation of the interplay between the purely dielectric and the magneto-optical responses, in terms of excitation of (and radiation by) two orthogonal electric dipoles. We analyze two different routes for the enhancement of the magneto-optical response with respect to the purely dielectric contribution, both based on the nanoparticle-surface interaction. The enhancement is discussed in terms of relevant magneto-optical signals, such as changes in reflectivity, polarization (Kerr) rotation, and ellipticityThis work was supported by the EU Project Nanomagma NMP3-SL-2008-21410

Magneto-optical kerr effect in resonant subwavelength nanowire gratings

Periodic arrays of nanorods can present a resonant response at specific geometric conditions. We use a multiple scattering approach to analyze the optical response of subwavelength nanowire gratings made of arbitrary anisotropic materials. When the rods are made of magneto-optical dielectrics we show that there is a complex interplay between the geometric resonances of the grating and the magneto-optical Kerr effects (MOKE) response. As we will show, for a given polarization of the incident light, a resonant magneto-optical response can be obtained by tuning the incidence angle and grating parameters to operate near the resonance condition for the opposite polarization. Our results could be important to understand and optimize MOKE structures and devices based on resonant subwavelength gratings and could open new perspectives in sensing applications. © 2014 IOP Publishing and Deutsche Physikalische Gesellschaft.This work was supported by Ikerbasque Visiting Fellowship (JJS), EU Project Nanomagma NMP3-SL-2008-214107, by LABEX WIFI (Laboratory of Excellence within the French Program 'Investments for the Future') under references ANR-10-LABX-24 and ANR-10-IDEX-0001-02 PSL*, by the Spanish Ministerio de Ciencia e Innovación through CSD2007-00046 (NanoLight.es); CSD2008-00023 (Funcoat); FIS2009-13430 ; MAT2011-29194-C02-01; FIS2012-3611 and by the Comunidad de Madrid P2009/TIC-1476.P2009/TIC-1476/MICROSERES-IIPeer Reviewe

Radiative corrections to the polarizability tensor of an electrically small anisotropic dielectric particle

Radiative corrections to the polarizability tensor of isotropic particles are fundamental to understand the energy balance between absorption and scattering processes. Equivalent radiative corrections for anisotropic particles are not well known. Assuming that the polarization within the particle is uniform, we derived a closed-form expression for the polarizability tensor which includes radiative corrections. In the absence of absorption, this expression of the polarizability tensor is consistent with the optical theorem. An analogous result for infinitely long cylinders was also derived. Magneto optical Kerr effects in non-absorbing nanoparticles with magneto-optical activity arise as a consequence of radiative corrections to the electrostatic polarizability tensor.This work has been supported by the EU NMP3-SL-2008-214107-Nanomagma, the Spanish MICINN Consolider NanoLight (CSD2007-00046), FIS2006-11170-C02-02 and by the Comunidad de Madrid Microseres-CM Program. R.G.-M. acknowledges support from the EU COST-MP0803. Work by R.G.-M. and L.S.F.-P. was supported by the MICINN “Juan de la Cierva” Program.Peer reviewe

Room Temperature Coherent and Voltage Tunable Terahertz Emission from Nanometer-Sized Field Effect Transistors

We report on reflective electro-optic sampling measurements of TeraHertz emission from nanometer-gate-length InGaAs-based high electron mobility transistors. The room temperature coherent gate-voltage tunable emission is demonstrated. We establish that the physical mechanism of the coherent TeraHertz emission is related to the plasma waves driven by simultaneous current and optical excitation. A significant shift of the plasma frequency and the narrowing of the emission with increasing channel's current are observed and explained as due to the increase of the carriers density and drift velocity.Comment: 3 figure

External excitation of hybrid plasma resonances in a gated semiconductor slab: An analytical study

International audienc

Plasma-resonant THz detection with HEMTs

International audienc