N. M. Bashara

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The types of error produced by beam deviation in the optical elements of an ellipsometer are examined. It is shown that there are two types of error that may be significant-systematic errors due to a variation in the plane of incidence and in the angle of incidence at the specimen and errors due to the combined effects of beam displacement and(More)
The loci of polarization states for which either the ellipticity alone or the azimuth alone remains invariant upon passing through an optical system are introduced. The cartesian equations of these two loci are derived in the complex plane in which the polarization states are represented. The equations are quartic and are conveniently expressed in terms of(More)
An optical system interposed in the path of a totally po­ larized light wave will, in general, induce changes in both the ellipticity and azimuth of the ellipse of polarization of the wave. However, there is one set of polarization states of the wave that propagate through the system with their ellipticity preserved and another set that pass through the(More)
Trajectories are given that describe the evolution of the ellipse of polarization in the complex plane for light propagating in a homogeneous anisotropic medium and along the helical axis of a cholesteric liquid crystal. For the general homogeneous anisotropic medium that exhibits combined birefringence and dichroism the trajectory is a spiral that(More)
Formulas by which the partial derivatives of the ellipsometric parameters psi and Delta with respect to the angle of incidence can be calculated are presented. These derivatives are plotted as a function of the angle of incidence, the refractive indices of the film, the substrate, and the immersion medium, and also as a function of film thickness on(More)
Beam deviation in the polarizing elements is identified as a significant source of error in existing ellipsometer alignment procedures. A high precision alignment procedure that eliminates these errors is described. This procedure is less time consuming than previous methods, and its accuracy is comparable to the limit of resolution of the ellipsometer(More)
A general procedure for the characterization of the optical parameters of a given surface using fixed wavelength multiple-angle-of-incidence ellipsometry is developed. Quantitative evaluation of estimated parameter precision is studied considering the sum of errors squared of a least squares fit, the parameter cross-correlation at this minimum, and the(More)