Realization of Multilayer Diffractive Components Experimental Methods of Characterization

Abstract

It has been shown that multilayer coatings permit to modify the optical properties of diffraction gratings[1], which increases the fields of application of gratings, especially in micro­optics domain. For example, the efficiency of a grating for s or p polarization can be varied by depositing an optical coating on the diffracting surface[2]. Several techniques can be used to realize such components. One can mention the evaporation techniques (Electron Beam Deposition, Ion Assisted Deposition, Ion Plating) already used for thin film applications. These techniques have been used in our laboratory to realize various diffractive components. The optical properties (efficiency of diffracted orders and phase difference of the scattered field between s and p polarizations) of such components, have been measured by using two devices: one based on a goniometric ellipsometer[3], the other based on a recently developed grating interferometer[4]. The results obtained with these two techniques have been analyzed and compared to the results given by a numerical simulation based on a rigourous method, and the absorption has been measured by using a photothermal technique[5].