197 research outputs found

    Trends in condensed matter physics: is research going faster and faster?

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    In this paper we study research trends in condensed matter physics. Trends are analyzed by means of the the number of publications in the different sub-fields as function of the years. We found that many research topics have a similar behavior with an initial fast growth and a next slower exponential decay. We derived a simple model to describe this behavior and built up some predictions for future trends

    Cavity Soliton Laser based on mutually coupled semiconductor microresonators

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    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

    Low frequency fluctuations in a Vertical Cavity Lasers: experiments versus Lang-Kobayashi dynamics

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    The limits of applicability of the Lang-Kobayashi (LK) model for a semiconductor laser with optical feedback are analyzed. The model equations, equipped with realistic values of the parameters, are investigated below solitary laser threshold where Low Frequency Fluctuations (LFF) are usually observed. The numerical findings are compared with experimental data obtained for the selected polarization mode from a Vertical Cavity Surface Laser (VCSEL) subject to polarization selective external feedback. The comparison reveals the bounds within which the dynamics of the LK can be considered as realistic. In particular, it clearly demonstrates that the deterministic LK, for realistic values of the linewidth enhancement factor α\alpha, reproduces the LFF only as a transient dynamics towards one of the stationary modes with maximal gain. A reasonable reproduction of real data from VCSEL can be obtained only by considering noisy LK or alternatively deterministic LK for extremely high α\alpha-values

    Cavity-soliton motion in the presence of device defects

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    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

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    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

    All-optical delay line using semiconductor cavity solitons (vol 92, 011101, 2008)

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    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

    Microresonator defects as sources of drifting cavity solitons

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    Cavity solitons (CS) are localized structures appearing as single intensity peaks in the homogeneous background of the field emitted by a nonlinear (micro)resonator. In real devices, their position is strongly influenced by the presence of defects in the device structure. In this Letter we show that the interplay between these defects and a phase gradient in the driving field induces the spontaneous formation of a regular sequence of CSs moving in the gradient direction. Hence, defects behave as a device built-in CS source, where the CS generation rate can be set by controlling the system parameters

    Microresonator defects as sources of drifting cavity solitons

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    Cavity solitons (CS) are localized structures appearing as single intensity peaks in the homogeneous background of the field emitted by a nonlinear (micro)resonator. In real devices, their position is strongly influenced by the presence of defects in the device structure. In this Letter we show that the interplay between these defects and a phase gradient in the driving field induces the spontaneous formation of a regular sequence of CSs moving in the gradient direction. Hence, defects behave as a device built-in CS source, where the CS generation rate can be set by controlling the system parameters
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