Showing papers by "Guilhem Gallot published in 2012"

Diffraction from a subwavelength elliptic aperture: analytic approximate aperture fields.

Abstract: An analytical approximate solution of the electromagnetic field on a subwavelength elliptical hole in a thin perfectly conducting screen is presented. Illumination is a linear polarized, normally incident plane wave. A polynomial development method is used and allows one to obtain an easy-to-use analytical solution of the fields, which can be used to build analytical expressions of aperture fields for apertures in anisotropic structures.

Optical activity of metallic helices in the terahertz domain: a theoretical investigation

Abstract: Optical activity in the terahertz spectral domain has recently seen a growing interest, but fine understanding of these phenomena is not yet developed. In this article, we study analytically the response of a metallic helix in the terahertz regime and present a full nonlocal calculation of its chiroptical response. Because we do not use multipolar expansion, this calculation is very general and applies to the case where the helix size is comparable to the wavelength of the light. We calculate the circular birefringence and dichroism in three configurations: propagation along or perpendicular to the helix axis and response of an isotropic distribution of such helices. We obtain analytical expressions and can examine the consequence of the breakdown of the multipolar expansion and the wavelength-dependence of the chiroptical response, as well as give orders of magnitude that compare favorably with experimental data. This calculation is also comforted by a finite element calculation.