Polarization independence of a one-dimensional grating in conical mounting

We demonstrate theoretically a polarization-independent guided-mode resonant filter with only a one dimensional grating. A rigorous method, the modal method by Fourier expansion, is used to compute the diffracted efficiencies of the grating. Wave-vector analysis fails to correctly design a polarization-independent structure. We show that a rigorous analysis of the resonances must be employed to obtain such a device; using a pole approach, we study the effects of grating parameters on the resonances of both polarizations.     

Impédance d’entrée d’antennes filaires

The input impedance calculation of wire antennas is carried out by solving an integrodifferential equation of the electric field by means of the method of moments. The presence of an imperfectly conducting half space intervenes directly in the computed expressions therefore requiring the determination of a great number of Sommerfeld integrals. Three methods of numerical computations of these integrals are compared.     

Rigorous and efficient grating-analysis method made easy for optical engineers

The coordinate-transformation-based differential method of Chandezon et al. [J. Opt. (Paris) 11, 235 (1980); J. Opt. Soc. Am. 72, 839 (1982)] (the C method) is one of the simplest and most versatile methods for modeling surface-relief gratings. However, to date it has been used by only a small number of people, probably because, traditionally, elementary tensor theory is used to formulate the method. We reformulate the C method without using any knowledge of tensor, thus, we hope, making the C method more accessible to optical engineers.     

Complex coordinate implementation in the curvilinear coordinate method: application to plane-wave diffraction by nonperiodic rough surfaces

We investigate the electromagnetic modeling of plane-wave diffraction by nonperiodic surfaces by using the curvilinear coordinate method (CCM). This method is often used with a Fourier basis expansion, which results in the periodization of both the geometry and the electromagnetic field. We write the CCM in a complex coordinate system in order to introduce the perfectly matched layer concept in a simple and efficient way. The results, presented for a perfectly conducting surface, show the efficiency of the model.     

Reformulation of the coordinate transformation method through the concept of adaptive spatial resolution. Application to trapezoidal gratings

We reformulate the coordinate transformation method for profiles represented by parametric equations. Numerically, the eigenvalue problem is solved by expanding both the electromagnetic field and the periodic coefficients of Maxwell's equations into Fourier series. For trapezoidal gratings, it is shown that the convergence of the method is closely related to the representation of the profile. A proper choice of the representation permits handling profiles that previously had been out of reach owing to their sharp edges. From a practical point of view, we are now able to analyze gratings with two vertical facets by using the coordinate transformation method.     

Differential covariant formalism for solving Maxwell's equations incurvilinear coordinates: oblique scattering from lossy periodic surfaces

A rigorous differential method describing the diffraction properties of lossy periodic surfaces is presented. A nonorthogonal coordinate system and a covariant formalism of Maxwell's equation are used simplifying boundary conditions expression. Only one eigenvalue system, unique for the TE and TM polarizations even for an oblique incidence, needs to be solved. Thus the numerical treatment is very efficient and CPU requirements significantly reduced. Numerical results are successfully compared with those obtained by an integral method using the boundary element method (BEM) as a numerical procedure