RESUMEN
The electric field immediately below an illuminated metal-film that is perforated with a hole array on a dielectric consists of direct transmission and scattering of the incident light through the holes and evanescent near-field from plasmonic excitations. Depending on the size and shape of the hole apertures, it exhibits an oscillatory decay in the propagation direction. This unusual field penetration is explained by the interference between these contributions, and is experimentally confirmed through an aperture which is engineered with four arms stretched out from a simple circle to manipulate a specific plasmonic excitation available in the metal film. A numerical simulation quantitatively supports the experiment. This fundamental characteristic will impact plasmonics with the near-fields designed by aperture engineering for practical applications.
RESUMEN
We present a new model of Bose-Einstein condensate dynamics based on strong confinement near the ground state. The model is based on a combined particle-wave view of the condensate and predicts oscillations in a two-component condensate, based on interference of nonspreading wave packets moving within a pair of tilted nearly square potentials. The oscillations are similar to those recently reported for a magnetically trapped 87Rb condensate, and the model's predictions give good quantitative agreement with the experiments.