B. Steinberger

Dielectric stripes on gold as surface plasmon waveguides

We report on surface plasmon polariton (SPP) waveguiding by SiO2 stripes on gold thin films. Compared to other SPP waveguide schemes, these systems provide relatively large effective refractive indices which can be described by the effective index method. By leakage radiation and near-field optical microscopy, we observe directly multimode and monomode behavior in straight SPP waveguides of different widths. Furthermore, we demonstrate waveguide bends and cross-talk free propagation across waveguide crossings.

Dielectric optical elements for surface plasmons

Basic optical elements for surface plasmons are fabricated and their functionality (focusing, refraction, and total internal reflection) is demonstrated experimentally. The optical elements consist of dielectric structures of defined geometry on top of a gold film. The working principle of these structures is discussed on the basis of calculated surface plasmon dispersion relations.

Quantitative analysis of surface plasmon interaction with silver nanoparticles

The present insight into plasmon effects on the nanoscale seems sufficiently advanced to allow the development of surface-plasmon-polariton- (SPP-) based optical devices. Therefore quantitative information describing SPP phenomena is required. We investigate a SPP beam splitter constituted by silver nanoparticles on a silver thin film, fabricated by electron-beam lithography. We acquire quantitative information on the beam splitter performance by monitoring SPP leakage radiation, yielding SPP reflection, transmission, and scattering efficiencies.

How to erase surface plasmon fringes

The authors report on the imaging of surface plasmon polaritons (SPPs) by leakage radiation microscopy in both direct and Fourier space. They show that manipulating the intensity distribution in the Fourier plane allows them to selectively image SPP beams propagating along specific directions. Thereby individual SPP beams are made accessible for direct quantitative analysis which is important in cases where the interaction between different SPP beams leads to interference fringes obscuring the individual components.

Dielectric stripes on gold as surface plasmon waveguides: Bends and directional couplers

Dielectric thin film stripes on a metal surface can be applied as surface plasmon (SP) waveguides. Here, the authors demonstrate experimentally that such structures can be used to build SP waveguide bends and couplers. On one hand, they show that SP transmission through a waveguide bend can be maximized by assuming the trade-off of propagation and bend induced radiation losses. On the other hand, the authors combine two waveguides to form a directional SP coupler.

Surface plasmon propagation in an elliptical corral

We report the experimental realization of an elliptical Bragg reflector acting as an interferometer for propagating surface plasmon (SP) waves. We investigate SP interferometry in this device using a leakage radiation microscope and we compare our observations with a theoretical model for SP propagation. Strong SP focalization as a function of laser polarization orientation is observed and justified.

Leakage radiation imaging of surface plasmon polaritons

The paper aims at the quantification of the interaction of surface plasmon polaritons (SPPs) in a metal thin film with lithographically tailored metal nanostructures which constitute the basic building blocks of the many SPP devices. Quantitative measurements are possible by monitoring the so-called leakage radiation (LR) which is inevitably present in SPP carrying thin films supported by a substrate.

Optical properties of tailor-made 1D and 2D noble metal particle arrays

By electron-beam lithography (EBL) 1D and 2D arrangements of metal nanoparticles can be fabricated with high control of particle shape, particle orientation and arrangement pattern. As the plasmon resonances in metal nanoparticles are primarily determined by the particle shape, their optical properties can be controlled within a wide range by design of the particle geometry parameters. Additionally, the control of local field effects, due to electrodynamic particle interaction, is possible by tailoring the interparticle distances and the specific arrangement pattern. Such EBL-produced metal nanoparticle thin films can be optimised for several optical properties, e.g. for defined dichroic behaviour. In particular our metal nanoparticle films can be used very efficiently in the field of surface enhanced optical effects. By plasmon resonance control defined energetic interactions between fluorophors and the metal nanoparticle can be obtained, leading to a control of balance between radiating and non-radiating deexcitation pathways. Thus, the fluorophor-particle interaction modifies the fluorophors absorption properties, its fluorescence intensities, fluorescence lifetime and photobleaching rates.