J. Salvi

90% Extraordinary optical transmission in the visible range through annular aperture metallic arrays

We demonstrate what we believe to be the first experimental extraordinary optical transmission (EOT) of up to 90%, thanks to a well-identified guided mode that propagates through annular apertures engraved into an optically thick silver layer. In spite of the metal losses, high transmission can be obtained by adjusting the geometrical parameters of the fabricated structure, as was already theoretically demonstrated. To our knowledge, this is the first study showing such a large transmission in the visible range.

Near-field optical images of subwavelength annular aperture arrays exhibiting an extraordinary transmission

In this paper, we present near‐field optical images of nanostructures exhibiting an extraordinary transmission. These structures consist of annular aperture arrays engraved in a metallic film: they are quite promising structures for nanophotonics because of their high transmission directly linked to a guided mode mediated by each annular aperture. We first briefly explain our fabrication process (focused ion beam milling), then we expose the experimental setup of the near‐field optical microscope working both in reflection and transmission modes. For the reflection mode, the ‘coffee‐bean’ structure of the electromagnetic field predicted by the theory has been quite well reproduced. For the transmission mode, we present preliminary experimental results concerning the influence of the wavelength and the polarization of the incident beam on the obtained near‐field images.

Use of a resonant optical cavity to increase the spectral density of near-field optical images

Abstract It has already been shown that the combination of an optical ring-cavity and of a Scanning tunneling optical microscopy (STOM) drastically reduces the evanescent decay of the evanescent field above the sample surface [Opt. Lett. 24 (1999) 1811] and accordingly, the spatial resolution is increased. In this paper a time–frequency analysis allows us to compare the quality of near-field images which are obtained for different positions along the cavity resonance curve.

Enhanced Optical Transmission Through Annular Aperture Arrays: Role of the Plasmonic Guided Modes

Let us recall what the enhanced or extraordinary optical transmission (EOT) is. This phraseology was firstly used by T. W. Ebbesen’s team in 1998 to qualify the far-field light transmission obtained through an array of cylindrical apertures engraved into an opaque metallic film [1–5]. It was noticed that the normalized measured transmission per aperture is very large compared to the transmission of a single aperture. Thus, the collective response of the whole structure is at the origin of this extraordinary effect. Nevertheless, this phenomenon becomes more usual for holes of big diameters compared to the illumination wavelength.

Enhanced transmission of light through coaxial nano-structures in a silver film : theory and first experimental results

Enhanced light transmission through metallic nanostructured films is considered. The response of nanometer annular apertures array in silver films are experimentally and theoretically investigated. The theory, the fabrication process and the experimental characterization are described. The calculations are based on a 3D Finite Difference Time Domain (FDTD) method. Concerning the experiments, optical far-field and near-field results are shown.

Resonant scanning tunneling optical microscope

It has been shown recently that a configuration combining near field detection and Fabry-Perot resonator offers a solution for increasing the signal to noise ratio. In this communication we use this conference as an interferometric imaging device. The basic idea behind this concept is that one way for enhancing the low sensitivity of such microscopes could consist of increasing the field intensity between tip and sample by either using a multi-reflection system such as a classical Fabry-Perot cavity or by using some more sophisticated multi-reflection devices.