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HL: Fachverband Halbleiterphysik

HL 22: Photonic crystals II

HL 22.10: Vortrag

Dienstag, 27. März 2007, 16:30–16:45, H13

Characterization of metamaterials based on split-ring-resonators — •Pia Weinmann, Martin Kamp, and Alfred Forchel — Technische Physik, Am Hubland, D-97074 Würzburg

Negative index materials are materials which have a negative permeability and permittivity in a certain frequency range. These metamaterials have recently attracted considerable attention due to their fascinating optical properties and potential applications. The challenge in realizing such metamaterials is to achieve a negative magnetic response. One possible approach is based on U-shaped Split-Ring-Resonators (SRR), which effectively operate as small LC-oscillators. The resonance of these structures leads to a negative effective permeability. In order to act as an effective medium, the spacing of the resonators has to be much smaller (usually a tenth) of the desired resonance wavelength. The resonace wavelength can be controlled by adjusting the dimensions of the Split-Ring-Resonators. We have investigated different resonator structures with magnetic resonances in the mid IR region. The structures were fabricated on silicon substrates by E-beam lithography, evaporation of gold and lift-off. The transmission of the samples in the range from 1.5 to 8μm was measured using a Fourier-Transform Infrared Spectrometer. Measurements on SRRs with different sizes and geometries show a clear dependence of the LC-resonance on structural dimensions. We have also investigated structures consisting of two gold wires separated by an insulating layer, which also provide the desired magnetic resonance.