14 research outputs found
Microwave response of a two-dimensional electron stripe
Electromagnetic response of a finite-width two-dimensional electron stripe is
theoretically studied. It is shown that retardation and radiative effects
substantially modify the absorption spectrum of the system at microwave
frequencies, leading to a non-trivial zigzag behavior of the
magnetoplasmon-polariton modes in magnetic fields, similar to that recently
observed by Kukushkin et al. [Phys. Rev. Lett. {\bf 90}, 156801 (2003)].Comment: 7 pages, 4 figure
Optical Kerr Effect in Graphene: Theoretical Analysis of the Optical Heterodyne Detection Technique
Graphene is an atomically thin two-dimensional material demonstrating strong
optical nonlinearities including harmonics generation, four wave mixing, Kerr
and other nonlinear effects. In this paper we theoretically analyze the optical
heterodyne detection (OHD) technique of measuring the optical Kerr effect (OKE)
in two-dimensional crystals and show how to relate the quantities measured in
such experiments with components of the third-order conductivity tensor
of the
two-dimensional crystal. Using results of a recently developed quantum theory
of the third-order nonlinear electrodynamic response of graphene we analyze the
frequency, charge carrier density, temperature and other dependencies of the
OHD-OKE response of this material. We compare our results with a recent OHD-OKE
experiment in graphene and find good agreement between the theory and
experiment.Comment: 14 pages, 7 figures, final versio
Electrically Tunable Optical Nonlinearities in Graphene-Covered SiN Waveguides Characterized by Four-Wave Mixing
We present a degenerate four-wave mixing experiment on a silicon nitride
(SiN) waveguide covered with gated graphene. We observe strong dependencies on
signal-pump detuning and Fermi energy, i.e. the optical nonlinearity is
demonstrated to be electrically tunable. In the vicinity of the interband
absorption edge () a peak value of the waveguide
nonlinear parameter of 6400 mW, corresponding to a
graphene nonlinear sheet conductivity A mV is measured
Influence of contacts on the microwave response of a two-dimensional electron stripe
Electromagnetic response of a finite-width two-dimensional electron stripe
with attached metallic side contacts is theoretically studied. It is shown that
contacts substantially influence the position, the linewidth, and the amplitude
of plasmon-polariton resonances in the stripe. In finite magnetic fields,
absorption of the wave with the inactive circular polarization (which is not
absorbed in an infinite system without contacts) may become larger than that of
the wave with the active polarization. The results are discussed in view of
recent microwave experiments in two-dimensional electron systems.Comment: 13 pages, incl. 9 figures, the paper has been substantially modified
and extended, new results have been added. Accepted for publication in Phys.
Rev.