The role of magnetoplasmons in Casimir force calculations

In this paper we review the role of magneto plasmon polaritons in the Casimir force calculations. By applying an external constant magnetic field a strong optical anisotropy is induced on two parallel slabs reducing the reflectivity and thus the Casimir force. As the external magnetic field increases, the Casimir force decreases. Thus, with an an external magnetic field the Casimir force can be controlled.The calculations are done in the Voigt configuration where the magnetic field is parallel to the slabs. In this configuration the reflection coefficients for TE and TM modes do not show mode conversion.Comment: contribution to QFEXT09, Norman, Oklahoma 200

Pull-in control due to Casimir forces using external magnetic fields

We present a theoretical calculation of the pull-in control in capacitive micro switches actuated by Casimir forces, using external magnetic fields. The external magnetic fields induces an optical anisotropy due to the excitation of magneto plasmons, that reduces the Casimir force. The calculations are performed in the Voigt configuration, and the results show that as the magnetic field increases the system becomes more stable. The detachment length for a cantilever is also calculated for a cantilever, showing that it increases with increasing magnetic field. At the pull-in separation, the stiffness of the system decreases with increasing magnetic field.Comment: accepted for publication in App. Phys. Let

Van der Waals torque induced by external magnetic fields

We present a method for inducing and controlling van der Waals torques between two parallel slabs using a constant magnetic field. The torque is calculated using the Barash theory of dispersive torques. In III-IV semiconductors such as $InSb$, the effect of an external magnetic field is to induce an optical anisotropy, in an otherwise isotropic material, that will in turn induce a torque. The calculations of the torque are done in the Voigt configuration, with the magnetic field parallel to the surface of the slabs. As a case study we consider a slab made of calcite and a second slab made of $InSb$. In the absence of magnetic field there is no torque. As the magnetic field increases, the optical anisotropy of $InSb$ increases and the torque becomes different from zero, increasing with the magnetic field. The resulting torque is of the same order of magnitude as that calculated using permanent anisotropic materials when the magnetic fields is close to 1 T.Comment: to appear in Journal of Applied Physic

La refracción negativa y los metamateriales: los nuevos materiales para dispositivos ópticos

En este trabajo describimos el efecto novel de la refracción negativa. Esta refracción anómala puede suceder en materiales artificiales: un tipo llamado metameteriales de índice de refracción negativa, en la cual la velocidad de fase es negativa y otro tipo de material de índice de refracción positiva donde la velocidad de grupo es positiva. Describimos modelos para la construcción de los materiales y damos ejemplos ilustrativos de la refracción negativa. También mencionamos algunas posibles aplicaciones de estos nuevos materiales como la construcción de lentes con superficies planas y materiales invisibles. En la fabricación de metamateriales que funcionen con luz visible, sus componentes deben tener tamaños en la nanoescala

Otto configuration for the TM and TE surface plasmon detection in doped graphene at terahertz frequencies

A numerical study of the TE and TM surface plasmon detection in free standing doped graphene by use of the Attenuated Total Reflectance technique is presented. It is demonstrated for both polarizations that the effects of wave interference can produce total absorption phenomenon

Transit times for electromagnetic waves in metallic layered systems

Metallic multilayered arrays are considered, in the local Drude theory, to investigate transit times of electromagnetic waves and the fast response mediated by plasmon polaritons. The transit times are calculated for frequencies corresponding to band gaps in the dispersion relation of periodic layered media. At these frequencies, and depending on the thickness of the structure, a fast response or even a superluminal effect is predicted. This effect is more evident near the plasmon polariton resonances. Moreover, the time delay is also affected by the surface plasmon coupling between the metallic layers. The metallic superlattices are described according to the Drude theory. (C) 2000 Published by Elsevier Science B.V. All rights reserved

Los números de fibonacci en la naturaleza y los sistemas nanoestructurados artificiales

Resumen: En este trabajo se describe y comenta la importancia y el impacto que los números de Fibonacci han tenido a lo largo de los años y su vinculación con el arte, la naturaleza y los materiales artificiales nanoestructurados, se hace una breve descripción sobre el momento histórico de su aparición, se revisan diversas formas de obtener la relación de recurrencia entre los números. Se muestran algunos ejemplos de su presencia en el arte, la naturaleza, así como resultados de propiedades ópticas de nanoestructuras de materiales artificiales construidos siguiendo esta secuencia

Transverse magnetic surface plasmons and complete absorption supported by doped graphene in Otto configuration

High sensitivity of the Attenuated Total Reflectance technique for exciting transverse magnetic surface plasmons in free-standing doped graphene is reported; complete agreement with the electromagnetic dispersion relation is numerically demonstrated in the terahertz regime. By reducing the air gap between prism and graphene in the Otto configuration we found that the surface plasmon excitation is weakened, but interference effects arise producing perfect absorption. At 5 THz two dips of zero-reflection were found, one of them with residual plasmonic contribution. Consequently, the reflection can be suppressed by changing the separation between prism and graphene; it is not needed to modify the graphene doping level. Conditions for destructive interference leading to complete absorption are presented and a particular behavior of the evanescent magnetic fields just at perfect absorption is reporte

Optical response of resonator induced plasmon filters: Nanometric diatomic structures

We investigate the optical response of plasmon filters, which are composed of a diatomic chain of metallic nanoclusters along which a resonator, composed of one or two metallic nanoclusters, is coupled vertically. Taking into account the resonator, we show that the transmission amplitude T of the electromagnetic radiation may display dips when the geometrical parameters are chosen properly. The presence of a resonator composed of one metallic nanocluster yields a dip at the cluster resonance frequency. When the resonator is composed of two nanoclusters, then if the nanoclusters are of the same material, two dips emerge as a consequence of the splitting of the dip of the one-nanocluster resonator. If the resonator is of two different materials, then we obtain two dips near the resonance frequencies of the nanoclusters. These dips appear when the separations between nanoclusters are properly adjusted. Such a device may be used to transfer directionally the electromagnetic radiation. In the limit of equal atomic nanoclusters we reproduce the monoatomic chain results (C) 2010 Elsevier Ltd. All rights reserve