29,309 research outputs found
Imaging ellipsometry of graphene
Imaging ellipsometry studies of graphene on SiO2/Si and crystalline GaAs are
presented. We demonstrate that imaging ellipsometry is a powerful tool to
detect and characterize graphene on any flat substrate. Variable angle
spectroscopic ellipsometry is used to explore the dispersion of the optical
constants of graphene in the visible range with high lateral resolution. In
this way the influence of the substrate on graphene's optical properties can be
investigatedComment: 3 pages, 3 figure
Optical properties of carbon nanofiber photonic crystals
Carbon nanofibers (CNF) are used as components of planar photonic crystals.
Square and rectangular lattices and random patterns of vertically aligned CNF
were fabricated and their properties studied using ellipsometry. We show that
detailed information such as symmetry directions and the band structure of
these novel materials can be extracted from considerations of the polarization
state in the specular beam. The refractive index of the individual nanofibers
was found to be n_CNF = 4.1.Comment: 10 pages, 4 figure
Low-temperature far-infrared ellipsometry of convergent beam
Development of an ellipsometry to the case of a coherent far infrared
irradiation, low temperatures and small samples is described, including a
decision of the direct and inverse problems of the convergent beam ellipsometry
for an arbitrary wavelength, measurement technique and a compensating
orientation of cryostat windows. Experimental results are presented: for a gold
film and UBe13 single crystal at room temperature (lambda=119 um), temperature
dependencies of the complex dielectric function of SrTiO3 (lambda=119, 84 and
28 um) and of YBa2Cu3O7-delta ceramic (lambda=119 um).Comment: 14 pages, 6 figure
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