H. Raether

Bio: H. Raether is an academic researcher from University of Hamburg. The author has contributed to research in topics: Surface plasmon & Surface finish. The author has an hindex of 19, co-authored 33 publications receiving 7438 citations. Previous affiliations of H. Raether include Munich University of Applied Sciences.

Energieanalyse in Kikuchi-Linien und in Reflexen einer Silizium-Spaltfläche

Abstract: The intensity of electrons (45 keV) scattered by Silicium cleavage surfaces (111) was measured by a Faraday cage. By means of an electrical retarding field the energy distribution of these electrons was determined: the Kikuchi lines and the Bragg maxima contain 95% resp. 80% of electrons with energy lossesΔE>5 eVolt. This high value of inelastically scattered electrons is theoretically unexplained. Applying plasma theory there is some difficulty to reconcile the presence of electrons with one energy loss in the Kikuchi lines with the small deflection which takes place in the elementary process of inelastic scattering.

Plasmaresonanzstrahlung von Silber

Abstract: The plasma resonance radiation of thin silver foils irradiated by light has been measured. The peak intensity is observed atλ=3275 A corresponding toħω=3.78 eV. The emitted light is fully polarised in the plane given by the normal of the foil and the direction of observation. A dependence of the intensity on the foil thickness, and on the angle of observation was found. The temperature influences the intensity and the peak position.

Über die charakteristischen Energieverluste bei Elektronenstreuung an Si-Spaltflächen

Abstract: The energy spectrum of electrons scattered inelastically at cleavage surfaces of silicon and germanium into Bragg reflection spots differs from that obtained by transmission by low lying characteristic energy losses. The dependence of their intensity on the order of the diffraction spots, on the surface roughness, and on the angle near the diffraction spot shows that they are due to surface plasma oscillations. The transmission energy spectrum is mainly due to the excitation of volume plasma oscillations.

Messung der Intensitäten von elastisch und unelastisch gestreuten Elektronen mit einer Gegenfeldanordnung

Abstract: A retarding field apparatus for the measurement of angular and energy distributions of scattered electrons (15 to 50 keV) is described. The apparatus was used for investigations into the influence of crystal size and electron energy on the elastically scattered intensity in Debye-Scherrer-diagramms of aluminium. The results are discussed with respect to the dynamical and kinematical theory. It proves, that the kinematical theory does not hold for crystallites of 100 A thickness or more.

Plasmonics for improved photovoltaic devices

Abstract: The emerging field of plasmonics has yielded methods for guiding and localizing light at the nanoscale, well below the scale of the wavelength of light in free space. Now plasmonics researchers are turning their attention to photovoltaics, where design approaches based on plasmonics can be used to improve absorption in photovoltaic devices, permitting a considerable reduction in the physical thickness of solar photovoltaic absorber layers, and yielding new options for solar-cell design. In this review, we survey recent advances at the intersection of plasmonics and photovoltaics and offer an outlook on the future of solar cells based on these principles.

Extraordinary optical transmission through sub-wavelength hole arrays

Abstract: The desire to use and control photons in a manner analogous to the control of electrons in solids has inspired great interest in such topics as the localization of light, microcavity quantum electrodynamics and near-field optics1,2,3,4,5,6. A fundamental constraint in manipulating light is the extremely low transmittivity of apertures smaller than the wavelength of the incident photon. While exploring the optical properties of submicrometre cylindrical cavities in metallic films, we have found that arrays of such holes display highly unusual zero-order transmission spectra (where the incident and detected light are collinear) at wavelengths larger than the array period, beyond which no diffraction occurs. In particular, sharp peaks in transmission are observed at wavelengths as large as ten times the diameter of the cylinders. At these maxima the transmission efficiency can exceed unity (when normalized to the area of the holes), which is orders of magnitude greater than predicted by standard aperture theory. Our experiments provide evidence that these unusual optical properties are due to the coupling of light with plasmons — electronic excitations — on the surface of the periodically patterned metal film. Measurements of transmission as a function of the incident light angle result in a photonic band diagram. These findings may find application in novel photonic devices.

Diamond-like amorphous carbon

Abstract: Diamond-like carbon (DLC) is a metastable form of amorphous carbon with significant sp3 bonding. DLC is a semiconductor with a high mechanical hardness, chemical inertness, and optical transparency. This review will describe the deposition methods, deposition mechanisms, characterisation methods, electronic structure, gap states, defects, doping, luminescence, field emission, mechanical properties and some applications of DLCs. The films have widespread applications as protective coatings in areas, such as magnetic storage disks, optical windows and micro-electromechanical devices (MEMs).

Surface plasmon resonance sensors: review

Abstract: Since the first application of the surface plasmon resonance (SPR) phenomenon for sensing almost two decades ago, this method has made great strides both in terms of instrumentation development and applications. SPR sensor technology has been commercialized and SPR biosensors have become a central tool for characterizing and quantifying biomolecular interactions. This paper attempts to review the major developments in SPR technology. Main application areas are outlined and examples of applications of SPR sensor technology are presented. Future prospects of SPR sensor technology are discussed.

High-impedance electromagnetic surfaces with a forbidden frequency band

Abstract: A new type of metallic electromagnetic structure has been developed that is characterized by having high surface impedance. Although it is made of continuous metal, and conducts dc currents, it does not conduct ac currents within a forbidden frequency band. Unlike normal conductors, this new surface does not support propagating surface waves, and its image currents are not phase reversed. The geometry is analogous to a corrugated metal surface in which the corrugations have been folded up into lumped-circuit elements, and distributed in a two-dimensional lattice. The surface can be described using solid-state band theory concepts, even though the periodicity is much less than the free-space wavelength. This unique material is applicable to a variety of electromagnetic problems, including new kinds of low-profile antennas.