The optical properties of few-layer graphene (FLG) films were measured in the ultraviolet and visible spectrum using a spectroscopic ellipsometer equipped with a 50-μm nominal microspot size. The FLG thickness was found by atomic force microscopy. Measurements revealed that the microspot is larger than the FLG flake. The ellipsometric data was interpreted using the island-film model. Comparison with graphite and recently published graphene data showed reasonable agreement, but with some features that could not be explained. The error margin for the optical constants was estimated to be ±10%.
Ellipsometry and infrared polarized reflection spectroscopy at oblique incidence of golden split-ring resonators were simulated and discussed. The ellipsometric spectra were related to the reflection spectra for the two polarization of the incident wave, s- and p-, with electric field being normal and parallel to the plane of incidence, respectively. Near-field and bulk current distribution at the resonances proved that they correspond to the multiple plasmonic modes of the split-ring resonators. The calculated magnetic moment showed that at oblique incidence both magnetic and electric field induce the magnetic resonances.
Electron transport through an InGaAs resonant tunneling structure with Rashba spin-orbit interaction and magnetic field parallel to the growth direction was studied theoretically. A nonequilibrium Green's function model was used, wherein interface roughness and longitudinal optical phonon scattering are treated in the self-consistent first Born approximation. The model predicts the main features of the two-dimensional magnetopolaron density of states and the secondary peaks in the I-V curve due to both resonant elastic and inelastic scattering. The I-V curves were studied at magnetic fields around the magnetophonon resonance and the elastic and inelastic contributions identified. At these fields (5 to 7 T), the current spin polarization was found to be dominated by the Zeeman effect and significant even in the presence of scattering events.