Philippe Lalanne

Learn More
The phenomenon of extraordinary light transmission through metallic films perforated by nanohole arrays at optical frequencies was first observed a decade ago and initiated important further experimental and theoretical work. In view of potential applications of such structures--for example, subwavelength optics, optoelectronics devices, and chemical(More)
A modified formulation of Maxwell's equations is presented that includes a complex and nonlinear coordinate transform along one or two Cartesian coordinates. The added degrees of freedom in the modified Maxwell's equations allow one to map an infinite space to a finite space and to specify graded perfectly matched absorbing boundaries that allow the(More)
The new formulation of the coupled-wave analysis recently proposed by Lalanne and Morris [J. that drastically improves the convergence performance of the method for lamellar gratings and for TM polarization is shown to be badly conditioned for gratings with a small thickness. Numerical evidence obtained with the coupled-wave analysis and with the(More)
We present a stable and efficient method for the Bloch-mode computation of one-dimensional grating waveguides. The approach uses the Fourier modal method and the S-matrix algorithm to remove numerical instabilities. The use of perfectly matched layers provide a high accuracy. Numerical results obtained for different lamellar grating waveguides and for both(More)
A metal film perforated by a regular array of subwavelength holes shows unexpectedly large transmission at particular wavelengths, a phenomenon known as the extraordinary optical transmission (EOT) of metal hole arrays. EOT was first attributed to surface plasmon polaritons, stimulating a renewed interest in plasmonics and metallic surfaces with(More)
We derive closed-form expressions for the effective index of subwavelength gratings up to the fourth and the second order for TE and TM polarization, respectively. These expressions are valid for arbitrary grating structures and are a generalization of previous results obtained for lamellar gratings with one groove per period (a structure often called a(More)
In this paper we investigate the potential of light trapping with diffraction gratings for organic solar cells. The architecture of the solar cell is based on conjugated polymers and a buckminsterfullerene derivative (PCBM), forming an interpenetrating donor-acceptor-network. The motivation for light trapping is the small absorptance of the photoactive(More)
The efficiency of conventional diffractive optical elements with échelette-type profiles drops rapidly as the illumination wavelength departs from the blaze wavelength. We use high dispersion of artificial materials to synthesize diffractive optical elements that are blazed over a broad spectral range (approximately 1 octave) or for two different(More)
Light localization due to random imperfections in periodic media is paramount in photonics research. The group index is known to be a key parameter for localization near photonic band edges, since small group velocities reinforce light interaction with imperfections. Here, we show that the size of the smallest localized mode that is formed at the band edge(More)