Near-grazing-angle reflectometry of absorbing media

摘要

A new technique to obtain the real and imaginary parts of the dielectric function of an absorbing medium in terms of the ratio R'_p/R'_s of the derivatives of p and s polarized light reflectances at the grazing and the normal incidence is developed. It is shown that this ratio can be expressed through the logarithmic derivatives (1/R)R' in the vicinity of the grazing angle. The using of both the normal - incidence and near - grazing angles measurements allows to overcome the instability (extreme sensitivity to experimental error) of all inversion of the polarized reflectances methods for absorbing media. The possibility of performing measurements without any angular adjustments is a great advantage of the present method. The unambiguity of this method is verified by the Jacobian formalism. It is important that errors in the measured parameters are not magnified when calculating the optical constants form the experimental data. We propsoe the practical implementation of this mehtod with variation of the nagle of incidence in an optical fashion. It permits to perform all the measurements appreciably aside from the grazing angle and greatly enhance the accuracy of these measurements.