PMID 23005567
DOI: 10.1103/PhysRevE.86.016711
WoS: 000306931100005
Résumé:

We employ a time-domain method to compute the near field on a contour enclosing infinitely long cylinders of arbitrary cross section and constitution. We therefore recover the cylindrical Hankel coefficients of the expansion of the field outside the circumscribed circle of the structure. The recovered coefficients enable the wideband analysis of complex systems, e. g., the determination of the radar cross section becomes straightforward. The prescription for constructing such a numerical tool is provided in great detail. The method is validated by computing the scattering coefficients for a homogeneous circular cylinder illuminated by a plane wave, a problem for which an analytical solution exists. Finally, some radiation properties of an optical antenna are examined by employing the proposed technique.

Ref HAL: hal-00808383_v1
DOI: 10.1117/12.893535
WoS: 000295963400015
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Résumé:

The strong coupling between a mode confined in a dielectric waveguide and a surface plasmon was demonstrated. It was shown that the strong and weak coupling regime can coexist. The strong coupling allows the spatial exchange of energy and opens a way towards the quantum control of plasmon, i.e. quantum plasmonics. © (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Ref HAL: hal-00808374_v1
DOI: 10.1109/ICTON.2011.5971082
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Résumé:

Guided modes in photonic structures are characterized by a propagation constant that is a root of pole of some operator. It is shown that the operatorial calculus of Dunford and Schwartz, i.e. the extension of Cauchy integrals to operators, provides a mean for the numerical computation of dispersion curves. The theory is developed and then applied in the case of a microstructured fibre.

Commentaires: http://www.ict.kth.se/MAP/FMI/Negonet/icton2011/

Ref HAL: hal-00808364_v1
DOI: 10.1117/12.892455
WoS: 000295935600013
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Résumé:

The homogenization of arrays of metallic rods was studied. Using standard homogenization theory, the effective permittivity was obtained. The onset of resonances was evidenced and showned to be linked with the negative sign of the real part of the permittivity. Numerical computations were performed to test the homogeneous model. © (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Ref HAL: hal-00808358_v1
Ref Arxiv: 1103.1404
DOI: 10.1117/1.3591367
WoS: 000291648000001
Ref. & Cit.: NASA ADS
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8 Citations
Résumé:

The field of nanophotonics witnesses a sort of golden age, where many new fields, such as plasmonics, metamaterials, transformation optics, have risen recently, leading to a wealth of new directions of research. The story started more than 20 years ago, when new artificial structures were imagined that could exhibit a photonic bandgap. These structures were called photonic crystals.1 They have carried a lot of hope on the possibility of molding the flow of light. It was indeed soon recognized that they could go way beyond the bandgap and that, in fact, they had a very rich band structure that allowed for control over the propagation of light itself, inside the photonic crystal. This has led to such effects as ultrarefraction, slow light, control of second harmonic emission, gradient photonic crystals, and negative refraction. Somehow, this wealth of properties has slowed down researches with the original quantum flavor of photonic crystals, at least as it appeared in the work of Sajeev John, which were seen really as devices able to control the Purcell effect. This was, for instance the case for the idea of realizing a laser cavity with a very low threshold. This aspect has shown a renewed interest recently.2

Commentaires: I thank G. Cassabois and M. Antezza for enlightening discussions. The financial support of the Institut Universitaire de France is gratefully acknowledged.

Ref HAL: hal-00808350_v1
DOI: 10.1117/1.3562938
WoS: 000289552000001
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1 Citation
Résumé:

The homogeneous and transport properties of a set of metallic fibers were studied. The existence of a plasma frequency was deduced and a precise formula for it was derived. A homogenized system for finite length ohmic wires was derived. Some numerical simulations were made to study the influence of disorder. The persistence of a low-frequency band gap was demonstrated numerically even in the case of a strong disorder. The existence of localized modes was explained in terms of the statistical properties of the medium.

Ref HAL: hal-00808333_v1
Ref Arxiv: 1003.6067
DOI: 10.1364/JOSAB.28.001275
Ref. & Cit.: NASA ADS
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Résumé:

It is well known that defining a local refractive index for a metamaterial requires that the wavelength be large with respect to the scale of its microscopic structure (generally the period). However, the converse does not hold. There are simple structures, such as the infinite, perfectly conducting wire medium, that remain nonlocal for arbitrarily large wavelength-to-period ratios. In this work, we extend these results to the case of finite wire media with finite conductivity, using a two-scale renormalization approach. We show that the nonlocality of the homogeneous model is so extreme that the permittivity is geometry dependent. Its accuracy is tested and confirmed numerically via full-vector three-dimensional finite element calculations. Moreover, lossy finite wire media exhibit large absorption with small reflection, while their low fill factor allows considerable freedom to control other characteristics of the metamaterial, such as its mechanical, thermal, or chemical robustness.