181 research outputs found
Signal amplification and control in optical cavities with off-axis feedback
We consider a large class of optical cavities and gain media with an off-axis
external feedback which introduces a two-point nonlocality. This nonlocality
moves the lasing threshold and opens large windows of control parameters where
weak light spots can be strongly amplified while the background radiation
remains very low. Furthermore, transverse phase and group velocities of a
signal can be independently tuned and this enables to steer it non
mechanically, to control its spatial chirping and to split it into two
counter-propagating ones.Comment: 4 pages, 4 picture
Features of the extreme events observed in the all-solid state laser with a saturable absorber
Extreme events (sometimes also called optical rogue waves), in the form of
pulses of extraordinary intensity, are easily observed in its chaotic regime if
the Fresnel number of the cavity is high. This result suggests that the
nonlinear interaction among transverse modes is an essential ingredient in the
formation of extreme events in this type of lasers, but there is no theoretical
description of the phenomenon yet. We report here a set of experimental results
on the regularities of these extreme events, to provide a basis for the
development of such a description. Among these results, we point out here: i)
the decay of the correlation across the transversal section of the laser beam,
and ii) the appearance of extreme events even if the time elapsed since the
previous pulse is relatively short (in terms of the average inter-pulse
separation), what indicates the existence of some unknown mechanism of energy
storage. We hypothesize that this mechanism is related with the imperfect
depletion of the gain by some of the transversal modes. We also present
evidence in support of this hypothesis.Comment: 9 pages, 9 figure
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
Influence of a Modulated Parameter on Hantavirus Infection
We study the dynamical behavior of a model commonly used to describe the infection of mice due to hantavirus (and, therefore, its possibility of propagation into human populations) when a parameter is changed in time. In particular, we study the situation when the ecological conditions (e.g., climate benignity, food availability, and so on) change periodically in time. We show that the density of infected mice increases abruptly as the parameter crosses a critical value. We correlate such a situation with the observed sudden outbreaks of hantavirus. Finally, we discuss the possibility of preventing a hantavirus epidemic.Fil: Torre, Maria Susana. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires. - Provincia de Buenos Aires. Gobernación. Comisión de Investigaciones Científicas. Centro de Investigaciones en Física e Ingeniería del Centro de la Provincia de Buenos Aires; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Exactas. Instituto de Física Arroyo Seco; ArgentinaFil: Acquaviva, Anaïs. Université de la Nouvelle Calédonie; FranciaFil: Boyer, Jean-Marc. Université de la Nouvelle Calédonie; FranciaFil: Tredicce, Jorge Raul. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin
All-optical delay line using semiconductor cavity solitons
An all-optical delay line based on the lateral drift of cavity solitons in semiconductor microresonators is proposed and experimentally demonstrated. The functionalities of the device proposed as well as its performance is analyzed and compared with recent alternative methods based on the decrease of group velocity in the vicinity of resonances. We show that the current limitations can be overcome using broader devices with tailored material responses
Cavity-soliton motion in the presence of device defects
Cavity solitons (CSs) are localized structures appearing as single intensity peaks in the homogeneous background of the field emitted by a nonlinear (micro) resonator driven by a coherent field (holding beam). By introducing a phase gradient in the holding beam, it is possible to induce CS drift. This motion is strongly influenced by the presence of defects in the device structure. We analyze numerically two situations that appeared in the experiments. In the first one, a structure is self-generated on the defect and a regular sequence of moving CS originates from it. We investigate the properties of this \u201ctap\u201d of CS as a function of the defect characteristics and of the parameters values. The second situation corresponds to the interaction between a moving CS and a defect, which plays a fundamental role in CS applications such as the delay line or the shift register
All-optical delay line using semiconductor cavity solitons (vol 92, 011101, 2008)
Correction of Pedaci, F. and Barland, S. and Caboche, E. and Firth, W.J. and Oppo, G.L. and Tredicce, J.R. and Ackemann, T. and Scroggie, A.J. (2008) All-optical delay line using semiconductor cavity solitons. Applied Physics Letters, 92 (1). ISSN 0003-695
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