Biomedical subjects

F J Garcia-Vidal

Publications and source records attributed to F J Garcia-Vidal.

4 recordsLinked to original sources

PubMed2006

Channel plasmon-polaritons: modal shape, dispersion, and losses.

We theoretically study channel plasmon-polaritons (CPPs) with a geometry similar to that in recent experiments at telecommunication wavelengths [Bozhevolnyi et al., Nature 440, 508 (2006)]. The CPP modal shape, dispersion relation, and losses are simulated by using the multiple multipole method and the finite difference time domain technique. It is shown that, with an increase of the wavelength, the fundamental CPP mode shifts progressively toward the groove opening, ceasing to be guided at the groove bottom and becoming hybridized with wedge plasmon-polaritons running along the groove edges.

Journal Article↗

PubMed2005

Tuning the conductance of single-walled carbon nanotubes by ion irradiation in the Anderson localization regime.

Carbon nanotubes are a good realization of one-dimensional crystals where basic science and potential nanodevice applications merge. Defects are known to modify the electrical resistance of carbon nanotubes; they can be present in as-grown carbon nanotubes, but controlling their density externally opens a path towards the tuning of the electronic characteristics of the nanotube. In this work, consecutive Ar+ irradiation doses are applied to single-walled nanotubes (SWNTs) producing a uniform density of defects. After each dose, the room-temperature resistance versus SWNT length (R(L)) along the nanotube is measured. Our data show an exponential dependence of R(L) indicating that the system is within the strong Anderson localization regime. Theoretical simulations demonstrate that mainly di-vacancies contribute to the resistance increase induced by irradiation, and that just a 0.03% of di-vacancies produces an increase of three orders of magnitude in the resistance of a SWNT of 400 nm length.

Computer Simulation↗

PubMed2004

Mimicking surface plasmons with structured surfaces.

Metals such as silver support surface plasmons: electromagnetic surface excitations localized near the surface that originate from the free electrons of the metal. Surface modes are also observed on highly conducting surfaces perforated by holes. We establish a close connection between the two, showing that electromagnetic waves in both materials are governed by an effective permittivity of the same plasma form. The size and spacing of holes can readily be controlled on all relevant length scales, which allows the creation of designer surface plasmons with almost arbitrary dispersion in frequency and in space, opening new vistas in surface plasmon optics.

Journal Article↗

PubMed2002

Beaming light from a subwavelength aperture.

Light usually diffracts in all directions when it emerges from a subwavelength aperture, which puts a lower limit on the size of features that can be used in photonics. This limitation can be overcome by creating a periodic texture on the exit side of a single aperture in a metal film. The transmitted light emerges from the aperture as a beam with a small angular divergence (approximately +/-3 degrees ) whose directionality can be controlled. This finding is especially surprising, considering that the radiating region is mainly confined to an area with lateral dimensions comparable to the wavelength of the light. The device occupies no more than one cubic micrometer and, when combined with enhanced transmission, suggests that a wide range of photonic applications is possible.

Journal Article↗