114 research outputs found
Nonlinear optical effects in artificial materials
We consider some nonlinear phenomena in metamaterials with negative
refractive index properties. Our consideration includes a survey of previously
known results as well as identification of the phenomena that are important for
applications of this new field. We focus on optical behavior of thin films as
well as multi-wave interactions.Comment: 22 pages, no figures. Submitted in book "Nonlinear waves in complex
systems: energy flow and geometry
Coherent Amplification of Optical Pulses in Metamaterials
In this paper we theoretically study propagation of steady state ultrashort
pulse in dissipative medium. We considered two cases (i) medium consists of
lossy metallic nanostructures embedded into a gain material and (ii) the gain
material is embedded directly into the nanostructures. We found the shape and
velocity of an optical pulse coupled with the polarization wave.Comment: 9 pages, 5 figures, submitted to IEEE Tran
Stochastic Pulse Switching in a Degenerate Resonant Optical Medium
Using the idealized integrable Maxwell-Bloch model, we describe random
optical-pulse polarization switching along an active optical medium in the
Lambda-configuration with disordered occupation numbers of its lower energy
sub-level pair. The description combines complete integrability and stochastic
dynamics. For the single-soliton pulse, we derive the statistics of the
electric-field polarization ellipse at a given point along the medium in closed
form. If the average initial population difference of the two lower sub-levels
vanishes, we show that the pulse polarization will switch intermittently
between the two circular polarizations as it travels along the medium. If this
difference does not vanish, the pulse will eventually forever remain in the
circular polarization determined by which sub-level is more occupied on
average. We also derive the exact expressions for the statistics of the
polarization-switching dynamics, such as the probability distribution of the
distance between two consecutive switches and the percentage of the distance
along the medium the pulse spends in the elliptical polarization of a given
orientation in the case of vanishing average initial population difference. We
find that the latter distribution is given in terms of the well-known arcsine
law
Optical Pulse Dynamics in Active Metamaterials with Positive and Negative Refractive Index
We study numerically the propagation of two-color light pulses through a
metamaterial doped with active atoms such that the carrier frequencies of the
pulses are in resonance with two atomic transitions in the
configuration and that one color propagates in the regime of positive
refraction and the other in the regime of negative refraction. In such a
metamaterial, one resonant color of light propagates with positive and the
other with negative group velocity. We investigate nonlinear interaction of
these forward- and backward-propagating waves, and find self-trapped waves,
counter-propagating radiation waves, and hot spots of medium excitation.Comment: 9 pages, 6 figure
Controlling pulse propagation in optical fibers through nonlinearity and dispersion management
In case of the nonlinear Schr\"odinger equation with designed group velocity
dispersion, variable nonlinearity and gain/loss; we analytically demonstrate
the phenomenon of chirp reversal crucial for pulse reproduction. Two different
scenarios are exhibited, where the pulses experience identical dispersion
profiles, but show entirely different propagation behavior. Exact expressions
for dynamical quasi-solitons and soliton bound-states relevant for fiber
communication are also exhibited.Comment: 4 pages, 5 eps figure
Effect of an Optical Negative Index Thin Film on Optical Bistability
We investigate nonlinear transmission in a layered structure consisting of a
slab of positive index material (PIM) with Kerr-type nonlinearity and a
sub-wavelength layer of linear negative index material (NIM) sandwiched between
semi-infinite linear dielectrics. We find that a thin layer of NIM leads to
significant changes in the hysteresis width when the nonlinear slab is
illuminated at an angle near that of total internal reflection. Unidirectional
diode-like transmission with enhanced operational range is demonstrated. These
results may be useful for NIMs characterization and for designing novel NIMs
based devices
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