Stéphane Roose

Design for polarizing holographic optical elements.

We present results of the application of a three-dimensional rigorous-vector coupled-wave theory to the design of polarizing holographic optical elements. Two different cases have been selected giving rise to two types of element, one of which is completely original. Experimental realizations were performed. The recording material was dichromated gelatin because of its outstanding performance related to diffraction efficiency. A fair agreement between the theoretical previsions and the experimental results was achieved.

An efficient interpolation algorithm for Fourier and diffractive optics

Abstract An alternative algorithm for the computation of diffraction (Fourier) integrals is described. Its computation time is comparable with the computation time of an FFT-algorithm combined with zero-framing. On the other hand it allows a free choice of resolution, as in numerical integration. The features of this algorithm are illustrated on the calculation of a PSF of an aberrated lens.

Computer-originated polarizing holographic optical element recorded in photopolymerizable layers.

The photosensitive system that is used in most cases to produce holographic optical holograms is dichromated gelatin. Other materials may be used, in particular, photopolymerizable layers. In the present investigation, we set out to use the polymer developed in the Laboratoire de Photochimie Générale in Mulhouse in order to duplicate a computer-generated hologram. Our technique is intended to generate polarizing properties. We took into account the fact that no wet chemistry processing is required; grating fringe spacings are not distorted through chemical development.

Description of diffractive optical elements with self-Fourier transform functions

In (synthetic) holography and diffractive optics, the optical field is often decomposed in a set of spherical or plane waves. This gives sometimes some problems in calculating the Fourier transform. Because Gaussian beams are their own Fourier transform, it seems to be more natural to use Gaussian beams as basis functions. However, because Gaussian functions are no complete set of basis functions, it is necessary to extend the idea and to use rather Gaussian-Hermite wave functions as an orthonormal basis set. Those ideas can also be applied to general Self-Fourier Transform functions.