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The characterization of the temporal profile of plasmonic fields is important both from the fundamental point of view and for potential applications in ultrafast nanoplasmonics. It has been proposed by Stockman et al (2007 Nat. Photonics 1 539) that the plasmonic electric field can be directly measured by the attosecond streaking technique; however, streaking from nanoplasmonic fields differs from streaking in the gas phase because of the field localization on the nanoscale. To understand streaking in this new regime, we have performed numerical simulations of attosecond streaking from fields localized in nanoantennas. In this paper, we present simulated streaked spectra for realistic experimental conditions and discuss the plasmonic field reconstruction from these spectra. We show that under certain circumstances when spatial averaging is included, a robust electric field reconstruction is possible. [ABSTRACT FROM AUTHOR]

A method is developed to produce chemically etched optical tips for near-field and confocal microscopies with valuable properties such as large transmission and no lateral light leaks. Prior to metal coating, tips are coated with a dielectric material, MgF2, that is refraction-index-matched to silica. It is shown that adjusting the MgF2 layer thickness allows us to control the tip aperture size in the diameter range from 70 to 500 nm. First, near-field fluorescence imaging of latex nanospheres with the smallest optical aperture tips confirms their ability to reach subwavelength optical resolution. In addition, thanks to their high transmission and collection efficiencies as well as their natural achromatism, it is proposed that the large optical aperture tips be advantageously substituted to high numerical aperture objectives in some confocal microscopes operating in constrained environments such as at low temperature. [ABSTRACT FROM AUTHOR]

We report on the resonant properties of platinum dipole antennas fabricated on a silicon-rich-oxinitride thin film that exhibits significant absorption in the mid-infrared of the electromagnetic spectrum (λ-1≈1100 cm-1). A nonlinear scaling between the resonant wavelength and the antenna length has been found and quantitatively confirmed by full-field electromagnetic simulations. The resonant wavelength increases linearly with antenna length for small lengths and tends to saturate for large ones (length >4 μm). This saturation effect is attributed to the coupling of a geometrical antenna resonance and an absorption resonance of the substrate material. [ABSTRACT FROM AUTHOR]

Centimeter sized arrays of gold coaxial rod-in-a tube cavities have been fabricated using anodized aluminum oxide as a template. The etching process used to create the cavities enables the production of extremely small gaps between tube and rod, on the order of 5 nm, smaller than those created by standard fabrication techniques. Normal incidence spectroscopy reveals two extinction peaks in the visible and near infrared wavelength range associated with resonant plasmonic modes excited in the structure. Numerical simulations show that the modes are associated with in-phase and out-of-phase hybridization of transverse dipolar excitations in the nanorod and in the tube. [ABSTRACT FROM AUTHOR]