The macroscopic permittivity tensors of a film-shaped metamaterial medium are calculated for the case when the charge carrier concentration N0 of each constituent of the composite metamaterial varies across the film thickness. The influence of an applied gate voltage on the surface plasmon resonances and on the optical properties of such a system are studied. Both homogeneous and perforated metallic slabs are investigated. Our simulations are based on Fourier series expansion of the electric potential which reduces the problem to a truncated system of complex linear equations. It is shown that the macroscopic effective permittivity tensor, as well as other optical properties of the metamaterial, are extremely sensitive to the applied gate voltage. This can be used to construct fast switches and other optical devices.
When an applied magnetic field has an arbitrary direction with respect to the lattice axes of a periodically nano-structured metal-dielectric metamaterial, the macroscopic or bulk effective permittivity tensor becomes anisotropic and all its components can be nonzero. This effect can be especially strong and significant in the vicinity of surface plasmon and cyclotron resonances (the frequencies of which are also sensitive to the value and direction of the applied external magnetic field). A similar effect for the case of dc effective conductivity is already verified experimentally (since magneto-conductivity tensor can be measured directly). However, this prediction for the permittivity has not yet been tested experimentally (since the permittivity tensor cannot be measured directly). What can be measured directly is the Voigt rotation, for which general exact analytical expressions were not published previously. In this work we have studied analytically and numerically the rotation and ellipticity of polarization of the light propagating through a metamaterial film with periodic nanostructure for arbitrary direction of the applied static magnetic field, including both Voigt and Faraday configurations. In the Voigt configuration we found a strong dependence of the above mentioned effects on the direction of the applied magnetic field.
When an applied magnetic field has an arbitrary direction with respect to the lattice axes of a periodically
microstructured or nanostructured metamaterial, the effective permittivity tensor of the metamaterial sample
becomes anisotropic and all its components can be nonzero. This is true even if the microstructure has a high
symmetry, e.g., cubic or triangular. It is found that the strong magneto-induced anisotropy which appears in the
macroscopic response leads to unusual anisotropic behavior of the Voigt effect and other magneto-optical (MO)
effects. I.e., these phenomena become strongly dependent on the direction of the applied static magnetic field,
as well as on the direction of the time dependent electromagnetic field, with respect to the symmetry axes of the
periodic microstructure.
The light transmission through metallic films with different types of nano-structures was studied both theoretically
and experimentally. It is shown, analytically, numerically and experimentally, that the positions of the
surface plasmon resonances depend on the nano-structural details. Those can be changed from sample to sample
or in given sample by applying an external dc electric or magnetic field. The dependence of transmission spectrum
on the shape of holes (inclusions) and external fields can be used for manipulation of the light transmission,
as well as the polarization of the transmitted light and other optical properties, by external field. Two complementary
situations are considered: a metal film with dielectric holes and a dielectric film with metallic islands.
In the case of metallic islands, we propose two ways of controlling plasmon resonance frequency: changing the
aspect ratio of the elliptical (or rectangular) islands and changing their mutual distances. For this case a new
analytical asymptotic approach for calculating the optical properties of such plasmonic systems is developed.
The results of our analytical and numerical studies are in good qualitative agreement with experiment.
The absorption spectrum of a
dielectric film with periodic array of metallic
islands of different shapes and different
mutual distances
was studied analytically, numerically,
and experimentally. We show that the
positions of the surface plasmon resonances depend on
the nano-structural details.
We propose two ways of controlling plasmon resonance frequency:
changing the aspect ratio
of the elliptical or rectangular islands and changing their
mutual distances.
A new analytical asymptotic approach for calculating the optical
properties of such plasmonic systems is developed.
The results of our analytical and numerical studies are in
good qualitative agreement with experiment.
The light transmission through metallic films with different types of nano-structures was studied both theoretically
and experimentally. It is shown, analytically, numerically and experimentally, that the positions of the
surface plasmon resonances depend on nano-structural details. This leads to a strong dependence of the amplitude
of the light transmission, as well as the polarization of the transmitted light and other optical properties, on
those details. Two complementary situations are considered: a metal film with dielectric holes and a dielectric
film with metallic islands. Two different possibilities for manipulating the light transmission are considered: One
is based upon application of a static magnetic field (actually, this is equivalent to changing the nano-structure
in a transformed configuration space), the other is based upon using liquid crystals as one of the constituents of
a nano-structured film.
We have conducted a theoretical and calculational study of the transmission of light through a sub-wavelength-perforated
metal film, as well as through a homogeneous metal film, with Drude ac conductivity tensor in
the presence of a static magnetic field. Both perforated and homogeneous metal films are found to exhibit a
magneto-induced light transparency and a decreasing of reflectivity due to cyclotron resonance. In particular, the
cyclotron resonance and the surface plasmon resonance of a perforated metal film move to higher frequencies with
increasing magnetic field, bringing about large changes in the extraordinary light transmission peaks predicted to
occur in such a film. In the case of periodic microstructures, these phenomena depend not only on the magnitude
of the applied in-plane magnetic field, but also on its direction. This is due to the nonlinear dependence of the
local electromagnetic response on that field. The practical possibility of changing the sample transparency by
application of a static magnetic field (e.g., a new type of magneto-optical switch) is discussed.
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