Ref HAL: hal-04170736_v1
Ref Arxiv: 2306.17640
Ref INSPIRE: 2673548
DOI: 10.1103/PhysRevA.108.062811
Ref. & Cit.: NASA ADS
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Résumé:

We investigate the Casimir-Lifshitz force (CLF) between two identical graphene strip gratings, laid on finite dielectric substrate. By using the scattering matrix (S-matrix) approach derived from the Fourier Modal Method with local basis functions (FMM-LBF), we fully take into account the high-order electromagnetic diffractions, the multiple scattering and the exact 2D feature of the graphene strips. We show that the non-additivity, which is one of the most interesting features of the CLF in general, is significantly high and can be modulated in situ without any change in the actual material geometry, by varying the graphene chemical potential. This study can open the deeper experimental exploration of the non-additive features of CLF with micro- or nano-electromechanical graphene-based systems.

Ref HAL: hal-04128464_v1
Ref Arxiv: 2305.18946
Ref INSPIRE: 2663857
DOI: 10.1103/PhysRevB.108.115412
Ref. & Cit.: NASA ADS
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Résumé:

We study the non equilibrium Casimir-Lifshitz force between graphene-based parallel structures held at different temperatures and in presence of an external thermal bath at a third temperature. The graphene conductivity, which is itself a function of temperature, as well as of chemical potential, allows us to tune in situ the Casimir-Lifshitz force. We explore different non equilibrium configurations while considering different values of the graphene chemical potential. Particularly interesting cases are investigated, where the force can change sign going from attractive to repulsive or where the force becomes non monotonic with respect to chemical potential variations, contrary to the behaviour under thermal equilibrium.

DOI: 10.1103/PhysRevE.107.025306
Résumé:

We present a numerical approach for the solution of electromagnetic scattering from a dielectric cylinder partially covered with graphene. It is based on a classical Fourier-Bessel expansion of the fields inside and outside the cylinder to which we apply ad hoc boundary conditions in the presence of graphene. Due to the singular nature of the electric field at the edges of the graphene sheet, we introduce auxiliary boundary conditions. The result is a particularly simple and efficient method allowing the study of diffraction from such structures. We also highlight the presence of multiple plasmonic resonances that we ascribe to the surface modes of the coated cylinder.

Ref HAL: hal-03826961_v1
DOI: 10.3390/s22218131
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Résumé:

We introduce a Domain Decomposition Spectral Method (DDSM) as a solution for Maxwell’s equations in the frequency domain. It will be illustrated in the framework of the Aperiodic Fourier Modal Method (AFMM). This method may be applied to compute the electromagnetic field diffracted by a large-scale surface under any kind of incident excitation. In the proposed approach, a large-size surface is decomposed into square sub-cells, and a projector, linking the set of eigenvectors of the large-scale problem to those of the small-size sub-cells, is defined. This projector allows one to associate univocally the spectrum of any electromagnetic field of a problem stated on the large-size domain with its footprint on the small-scale problem eigenfunctions. This approach is suitable for parallel computing, since the spectrum of the electromagnetic field is computed on each sub-cell independently from the others. In order to demonstrate the method’s ability, to simulate both near and far fields of a full three-dimensional (3D) structure, we apply it to design large area diffractive metalenses with a conventional personal computer.

Ref HAL: hal-03692515_v1
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We present an accurate and simple semi analytical model for investigating the magneto-plasmonic response of a 1D subwavelength graphene strip grating under an external static magnetic field when the graphene is considered as an anisotropic layer with atomic thickness. It is based on an effective medium approach (EMA) and a rigorous phase correction. The proposed model is numerically validated and evaluated by comparing the results with those obtained from the PMM method and from methods published in the litterature.

Ref HAL: hal-03692467_v1
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We will discuss some recent numerical results on the Casimir interaction between metallic gratings [1, 2, 3] . These findings pave the way to the design of a contactless quantum vacuum torsional spring, and sensors with possi- ble relevance to micro and nanomechanical devices.

Ref HAL: hal-03692457_v1
Exporter : BibTex | endNote
Résumé:

We present a numerical approach for the solution of EM scattering from a dielectric cylinder partially covered with graphene. It is based on a classical Fourier-Bessel expan- sion of the fields inside and outside the cylinder to which we apply the ad-hoc boundary conditions in the presence of graphene. Due to the singular nature of the electric field at the ends of the graphene sheet, we introduce auxiliary boundary conditions to better take this reality into account. The result is a very simple and very efficient method allow- ing the study of diffraction from such structures.