Multilevel fast multipole method based on a potential formulation for 3D electromagnetic scattering problems.

A combination of the multilevel fast multipole method (MLFMM) and boundary element method (BEM) can solve large scale photonics problems of arbitrary geometry. Here, MLFMM-BEM algorithm based on a scalar and vector potential formulation, instead of the more conventional electric and magnetic field formulations, is described. The method can deal with multiple lossy or lossless dielectric objects of arbitrary geometry, be they nested, in contact, or dispersed.

Focussing light through a stack of toroidal channels in PMMA.

We propose a transformational design of an axi-symmetric gradient lens for electromagnetic waves. We show that a metamaterial consisting of toroidal air channels of diameters ranging from 23 nm to 190 nm in a matrix of Polymethylmethacrylate (PMMA) allows for a focussing effect of light over a large bandwidth i.e.

Perturbation method for the Rigorous Coupled Wave Analysis of grating diffraction.

The perturbation method is combined with the Rigorous CoupledWave Analysis (RCWA) to enhance its computational speed. In the original RCWA, a grating is approximated by a stack of lamellar gratings and the number of eigenvalue systems to be solved is equal to the number of subgratings. The perturbation method allows to derive the eigensolutions in many layers from the computed eigensolutions of a reference layer provided that the optical and geometrical parameters of these layers differ only slightly.

Polarization-sensitive printing of surface plasmon interferences.

Surface plasmon assisted lithography is currently a matter of growing interest since it allows nanopatterning in photosensitive films without being restricted by the diffraction limit. Using specially designed metallic nanostructures coated with a photosensitive azobenzene-dye polymer, we have generated a plasmon interference field in the polymer layer. The atomic force microscopy observation of the azo-dye polymer surface after exposure exhibits complex topographies which are found to be well explained by an analytically computed surface plasmon interference model that highlights the polarization influence on the pattern shape.