Alfred Leitner

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We propose the idea of a subwavelength-sized light guide represented by a linear chain of spherical metal nanoparticles in which light is transmitted by electrodynamic interparticle coupling. The light-transport properties of this system are investigated by use of model calculations based on generalized Mie theory. Considering Ag particles of 50-nm(More)
From 1988 to 1996, 121 femoral shaft fractures in children were treated by external fixation. The average age was 8.4 years (range: 2 to 16 years). Thirty-three children sustained multiple injuries (27%), and 13 children had 2nd- or 3rd-degree open fractures (10.7%). This study not only analyzes the expenditure of the operation and the corresponding(More)
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(More)
We present Raman spectra and Raman images of the methylene blue molecule adsorbed as a single layer on gold nanoparticles regularly arranged in periodic arrays. Spectra and images are recorded in the same spatial and spectral regions using an excitation under total internal reflection. Images of the Raman scattering appear as spots of circular shape located(More)
We report the realization of two-dimensional optical wavelength demultiplexers and multiports for surface plasmons polaritons (SPPs) based on plasmonic crystals, i.e., photonic crystals for SPPs. These SPP elements are built up of lithographically fabricated gold nanostructures on gold thin films. We show by direct imaging of laterally confined SPP beams in(More)
Films of identically shaped, elongated, and parallel-oriented metal nanoparticles arranged in a regular pattern upon a transparent substrate were produced by use of electron-beam lithography. Because of the strong difference in the particles' polarizability components, the optical extinction spectra show strong dichroism. Moreover, one can shift the(More)
We describe a surface plasmon polariton- (SPP-) based device for measuring the intensity distribution of strongly focused light beams. A gold thin film configured as a sharp step is positioned in the focal region of a light beam, converting light into SPPs. The SPPs emit directional leakage radiation into the glass substrate beneath the thin film. The(More)
In metal nanoparticles the resonance wavelength of light-driven collective electron oscillations is determined by the particle shape. This shape dependence can be used for optical data storage by spectral coding. In this way the storage density can be increased by at least a factor of 5 compared with that for conventional optical storage principles.
Lithographically designed two-dimensional arrays consisting of gold nanoparticles deposited on a smooth gold film are used as substrate to examine the SERS effect of the trans-1,2-bis (4-pyridyl) ethylene molecule. These arrays display two plasmon bands instead of the single one observed for the same arrays of particles but deposited on indium tin oxide(More)
We show experimentally and numerically that Forster-type resonant energy transfer between molecules strongly depends on the interaction with plasmonic resonances in a nearby metallic nanoparticle (MNP). Acceptor luminescence emerges at the expense of donor luminescence when an acceptor molecule harvests the donor's near-field energy. By tuning the resonance(More)