Interferometric characterization of subwavelength lamellar gratings.
We propose a new, to our knowledge, method for determining the two main critical parameters of periodic one-dimensional lamellar structures, namely, linewidths and etched depths. The method is simple and requires only two measurements for the phase of the zero-transmitted order under two orthogonal polarizations. It is inspired by the analogy between subwavelength gratings and anisotropic homogeneous thin films. The method is tested with experimental data obtained with a Mach-Zehnder interferometer. Etched depths and linewidths derived from the interferograms and electromagnetic theory are compared with scanning-electron-microscope observations.
Lalanne
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Laboratoire Charles Fabry de l'Institut d'Optique, Centre National de la Recherche Scientifique, BP 147, F-91403 Orsay cedex, France. philippe.lalanne@iota.u-psud.fr
Pichon
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Chavel
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Cambril
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Launois
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