Generalized Null-Ellipsometry in the Polarizer-Sample-Analyzer Scheme

The null ellipsometry technique of generalized ellipsometry based on using a compensator-free polarizer-sample-analyzer scheme for the case of incidence of an s- or p-polarized light on an anisotropic system is analyzed. Analytical expressions establishing a relation between measured angular quantity (analyzer azimuth at minimum intensity of detected radiation) and elements of the (2 x 2) anisotropic Jones matrix are derived. The dependence of this angular quantity on sample orientation (azimuth) is proposed to be used for determining optic-geometrical parameters of studied anisotropic systems. Sensitivity of the proposed method is estimated and is found to be comparable with that of the polarizer-compensator-sample-analyzer scheme. A comparative analysis of the discussed method with the well-known photometric method of generalized ellipsometry in the polarizer-sample-analyzer scheme based on measurement of the dependence of reflected-light intensity on sample azimuth at fixed polarizer and analyzer positions is presented. It is estimated that an error of a single arc minute in the proposed method and a relative error of determining the energy reflection coefficient of 0.05% in the photometric method of the generalized ellipsometry correspond to the same sensitivity.