164 research outputs found
Deterministic control of broadband light through a multiply scattering medium via the multispectral transmission matrix
We present a method to measure the spectrally-resolved transmission matrix of
a multiply scattering medium, thus allowing for the deterministic
spatiospectral control of a broadband light source by means of wavefront
shaping. As a demonstration, we show how the medium can be used to selectively
focus one or many spectral components of a femtosecond pulse, and how it can be
turned into a controllable dispersive optical element to spatially separate
different spectral components to arbitrary positions.Comment: minor changes, with additional discussion of the results. Fig 4 now
split into two separate figure
Fluctuations in random networks: non-linear model description
Disordered networks are known to be an adequate model for describing
fluctuations of electric fields in a random metal-dielectric composite. We show
that under appropriate conditions the statistical properties of such a system
can be studied in the framework of the Efetov's non-linear model.
This fact provides a direct link to the theory of Anderson localization.Comment: 4 pages, latex, no figure
Coherent spatio-temporal control of pulsed light through multiple scattering media
We report broadband characterization of the propagation of light through a multiply
scattering medium by means of its Multi-Spectral Transmission Matrix. Using a single
spatial light modulator, our approach enables the full control of both spatial and spectral
properties of an ultrashort pulse transmitted through the medium. We demonstrate
spatiotemporal focusing of the pulse at any arbitrary position and time with any desired
spectral shape. Our approach opens new perspectives for fundamental studies of lightmatter
interaction in disordered media, and has potential applications in coherent control
and imaging
Coherent Backscattering of Light by Cold Atoms
Light propagating in an optically thick sample experiences multiple
scattering. It is now known that interferences alter this propagation, leading
to an enhanced backscattering, a manifestation of weak localization of light in
such diffuse samples. This phenomenon has been extensively studied with
classical scatterers. In this letter we report the first experimental evidence
for coherent backscattering of light in a laser-cooled gas of Rubidium atoms.Comment: 4 pages REVTEX, 1 page color image GIF, accepted for publication in
Phys. Rev. Let
Pruning waste management and climate change in Sierra Mágina's olive groves (Andalusia, Spain)
Unidad de excelencia María de Maeztu MdM-2015-0552In the context of climate change, concern is raising about the negative effects of some pruning waste management practices. On the one hand, burning of pruning residue is seen as controversial regarding its contribution to greenhouse gas emissions. On the other hand, chipping the wood and using it as mulch is seen as highly risky regarding pest and disease control. Considering these issues, it is important to try to understand how and why these practices are adopted. In this study, we conducted in-depth interviews and survey questionnaires in the olive-growing region of Sierra Mágina (Andalusia) in order to explore (1) which were the pruning waste management practices in place, (2) which had been these practices in the past, and (3) which were the factors influencing the choice of different practices. Since 2010, there has been a shift in pruning waste management practices in this region, from stubble burning to chipping. This change seems to be led by older/retired farmers that have young and non-inherited groves. Moreover, this change is shown not to be necessarily a result of "greening" in agriculture but rather a result of intensification and mechanization. These results are discussed regarding the processes of innovation adoption in the region and the possible unforeseen externalities that derive from this change in pruning waste management practices
Pruning waste management and climate change in Sierra Mágina's olive groves (Andalusia, Spain)
Unidad de excelencia María de Maeztu MdM-2015-0552In the context of climate change, concern is raising about the negative effects of some pruning waste management practices. On the one hand, burning of pruning residue is seen as controversial regarding its contribution to greenhouse gas emissions. On the other hand, chipping the wood and using it as mulch is seen as highly risky regarding pest and disease control. Considering these issues, it is important to try to understand how and why these practices are adopted. In this study, we conducted in-depth interviews and survey questionnaires in the olive-growing region of Sierra Mágina (Andalusia) in order to explore (1) which were the pruning waste management practices in place, (2) which had been these practices in the past, and (3) which were the factors influencing the choice of different practices. Since 2010, there has been a shift in pruning waste management practices in this region, from stubble burning to chipping. This change seems to be led by older/retired farmers that have young and non-inherited groves. Moreover, this change is shown not to be necessarily a result of "greening" in agriculture but rather a result of intensification and mechanization. These results are discussed regarding the processes of innovation adoption in the region and the possible unforeseen externalities that derive from this change in pruning waste management practices
Infrared near-field microscopy with the Vanderbilt free electron laser: overview and perspectives
Étude sociale d'un port au XVe siècle d'après ses registres de comptes : Dieppe
Gresillon Sylviane. Étude sociale d'un port au XVe siècle d'après ses registres de comptes : Dieppe. In: École pratique des hautes études. 4e section, Sciences historiques et philologiques. Annuaire 1970-1971. 1971. pp. 883-885
La ville et nous, géographes (en 1995)
Gresillon Michel. La ville et nous, géographes (en 1995). In: L'information géographique, volume 60, n°2, 1996. pp. 81-85
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