Biomedical subjects

Anne Sentenac

Publications and source records attributed to Anne Sentenac.

3 recordsLinked to original sources

PubMed2003

Study of waveguide grating eigenmodes for unpolarized filtering applications.

The dispersion relation of eigenmodes of two-dimensional waveguide gratings is studied with a perturbative model. The analytic expression of the complex wavelength of the modes permits us to predict the shape of the anomalies in the grating reflectivity with respect to the wavelength and the polarization of the incident plane wave. The simultaneous excitation of two independent modes is necessary for obtaining high-efficiency filtering of unpolarized light. We show how this requirement can be met.

Journal Article↗

PubMed2003

High-resolution optical diffraction microscopy.

In an optical diffraction microscopy experiment, one measures the phase and amplitude of the field diffracted by the sample and uses an inversion algorithm to reconstruct its map of permittivity. We show that with an iterative procedure accounting for multiple scattering, it is possible to visualize details smaller than lambda/4 with relatively few illumination and observation angles. The roles of incident evanescent waves and noise are also investigated.

Journal Article↗

PubMed2002

Phenomenological theory of filtering by resonant dielectric gratings.

Using a phenomenological theory of diffraction gratings made by perturbing a planar waveguide allows us to deduce important properties of the sharp filtering phenomena generated by this kind of structure when the incident light excites a guided wave. It is shown that the resonance phenomenon occurring in these conditions acts on one of the two eigenvalues of the Hermitian reflection matrix only. As a consequence, we deduce a mathematical expression of the reflectivity and demonstrate that high-efficiency filtering of unpolarized light requires the simultaneous excitation of two uncoupled guided waves. Numerical examples are given.

Journal Article↗