0000000000014816

AUTHOR

Maria Allegrini

showing 3 related works from this author

Determinant role of the edges in defining surface plasmon propagation in stripe waveguides and tapered concentrators

2012

International audience; In this paper, we experimentally show the effect of waveguide discontinuity on the propagation of the surface plasmon in metal stripes and tapered terminations. Dual-plane leakage microscopy and near-field microscopy were performed on Au stripes with varied widths to imag29e the surface plasmon intensity distribution in real and reciprocal spaces. We unambiguously demonstrate that edge diffraction is the limiting process determining the cutoff conditions of the surface plasmon mode. Finally, we determine the optimal tapered geometry leading to the highest transmission.

DiffractionTotal internal reflectionMaterials sciencebusiness.industrySurface plasmonNanophotonicsPhysics::OpticsStatistical and Nonlinear Physics02 engineering and technology021001 nanoscience & nanotechnology01 natural sciencesSurface plasmon polaritonAtomic and Molecular Physics and Opticslaw.inventionOpticslaw0103 physical sciencesNear-field scanning optical microscope[ SPI.NANO ] Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics[SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics010306 general physics0210 nano-technologybusinessWaveguideLocalized surface plasmon
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Nonlinear radiation imprisonment in magneto-optical vapor traps

2008

We analyze nonlinear radiation imprisonment (RI) effects in an optically thick vapor in different temperature regimes. An analytical approach is proposed to treat nonlinear decay problems. Special attention is paid to vapor samples having curvilinear geometries (cylinder, sphere) and being excited by a strong laser pulse. We derive a number of new formulas for different radiative trapping factors as functions of opacity and propose a general approach for RI evaluation allowing us to deal with samples both at room and low, or very low, temperatures, such as those customarily achieved in magneto-optical trap (MOT) experiments. As a result, we predict a "subnatural" decay of radiation escaping…

PhysicsOpacityANALYTICALLY SOLVABLE PROBLEMSRESONANCE RADIATIONRadiationLaserResonance (particle physics)Atomic and Molecular Physics and Opticslaw.inventionNonlinear systemlawExcited stateVELOCITY REDISTRIBUTIONRadiative transferCylinderPhysics::Atomic PhysicsAtomic physicsEXCITATION TRANSFEREXCITED ATOMS
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Nonlinear effects in optical pumping of a cold and slow atomic beam

2015

By photoionizing hyperfine (HF) levels of the Cs state $6{\phantom{\rule{0.16em}{0ex}}}^{2}{P}_{3/2}$ in a slow and cold atom beam, we find how their population depends on the excitation laser power. The long time (around $180\phantom{\rule{4pt}{0ex}}\ensuremath{\mu}\mathrm{s})$ spent by the slow atoms inside the resonant laser beam is large enough to enable exploration of a unique atom-light interaction regime heavily affected by time-dependent optical pumping. We demonstrate that, under such conditions, the onset of nonlinear effects in the population dynamics and optical pumping occurs at excitation laser intensities much smaller than the conventional respective saturation values. The ev…

Physicseducation.field_of_studyPopulation02 engineering and technologysaturation spectroscopy; mutilevel atoms; cesium; laser; absorption: photoionization; intesity; systems; state; trap021001 nanoscience & nanotechnologyLaser01 natural sciencesAtomic and Molecular Physics and OpticsNumerical integrationlaw.inventionOptical pumpinglawUltracold atom0103 physical sciencesPhysics::Atomic PhysicsLaser power scalingAtomic physics010306 general physics0210 nano-technologyeducationHyperfine structureExcitationPhysical Review A
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