478 research outputs found
Cavity Soliton Laser based on mutually coupled semiconductor microresonators
We report on experimental observation of localized structures in two mutually
coupled broad-areahttp://hal.archives-ouvertes.fr/images/calendar.gif
semiconductor resonators. These structures coexist with a dark homogeneous
background and they have the same properties as cavity solitons without
requiring the presence of a driving beam into the system. They can be switched
individually on and off by means of a local addressing beam
Generation of unipolar pulses in a circular Raman-active medium excited by few-cycle optical pulses
We study theoretically a new possibility of unipolar pulses generation in
Raman-active medium excited by a series of few-cycle optical pulses. We
consider the case when the Raman-active particles are uniformly distributed
along the circle, and demonstrate a possibility to obtain a unipolar
rectangular video pulses with an arbitrarily long duration, ranging from a
minimum value equal to the natural period of the low frequency vibrations in
the Raman-active medium
Dissipative solitons which cannot be trapped
In this paper we study the behavior of dissipative solitons in systems with
high order nonlinear dissipation and show how they cannot survive under the
effect of trapping potentials both of rigid wall type or asymptotically
increasing ones. This provides an striking example of a soliton which cannot be
trapped and only survives to the action of a weak potential
Generation of unipolar half-cycle pulse via unusual reflection of a single-cycle pulse from an optically thin metallic or dielectric layer
We present a significantly different reflection process from an optically
thin flat metallic or dielectric layer and propose a strikingly simple method
to form approximately unipolar half-cycle optical pulses via reflection of a
single-cycle optical pulse. Unipolar pulses in reflection arise due to
specifics of effectively one-dimensional pulse propagation. Namely, we show
that in considered system the field emitted by a flat medium layer is
proportional to the velocity of oscillating medium charges instead of their
acceleration as it is usually the case. When the single-cycle pulse interacts
with linear optical medium, the oscillation velocity of medium charges can be
then forced to keep constant sign throughout the pulse duration. Our results
essentially differ from the direct mirror reflection and suggest a possibility
of unusual transformations of the few-cycle light pulses in linear optical
systems
Realization of a semiconductor-based cavity soliton laser
The realization of a cavity soliton laser using a vertical-cavity
surface-emitting semiconductor gain structure coupled to an external cavity
with a frequency-selective element is reported. All-optical control of bistable
solitonic emission states representing small microlasers is demonstrated by
injection of an external beam. The control scheme is phase-insensitive and
hence expected to be robust for all-optical processing applications. The
motility of these structures is also demonstrated
Patterns and localized structures in bistable semiconductor resonators
We report experiments on spatial switching dynamics and steady state
structures of passive nonlinear semiconductor resonators of large Fresnel
number. Extended patterns and switching front dynamics are observed and
investigated. Evidence of localization of structures is given.Comment: 5 pages with 9 figure
Negative diffraction pattern dynamics in nonlinear cavities with left-handed materials
We study a ring cavity filled with a slab of a right-handed material and a
slab of a left-handed material. Both layers are assumed to be nonlinear Kerr
media. First, we derive a model for the propagation of light in a left-handed
material. By constructing a mean-field model, we show that the sign of
diffraction can be made either positive or negative in this resonator,
depending on the thicknesses of the layers. Subsequently, we demonstrate that
the dynamical behavior of the modulation instability is strongly affected by
the sign of the diffraction coefficient. Finally, we study the dissipative
structures in this resonator and reveal the predominance of a two-dimensional
up-switching process over the formation of spatially periodic structures,
leading to the truncation of the homogeneous hysteresis cycle.Comment: 8 pages, 5 figure
Self-organization, pattern formation, cavity solitons, and rogue waves in singly resonant optical parametric oscillators
The spatiotemporal dynamics of singly resonant optical parametric oscillators with external seeding displays hexagonal, roll, and honeycomb patterns, optical turbulence, rogue waves, and cavity solitons. We derive appropriate mean-field equations with a sinc2 nonlinearity and demonstrate that off-resonance seeding is necessary and responsible for the formation of complex spatial structures via self-organization. We compare this model with those derived close to the threshold of signal generation and find that back-conversion of signal and idler photons is responsible for multiple regions of spatiotemporal self-organization when increasing the power of the pump field
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