Reflection of light from nanoscopically stratified anisotropic media and optical probing of dielectric nanofilms

The reflection of linearly polarized light from a layered nanoscopic system of anisotropic dielectric films on homogeneous isotropic substrate is investigated in the long-wavelength limit. The expressions for reflection characteristics of an N-layer system of arbitrarily anisotropic ultrathin films are derived. The analytical results are supported by computer-aided analysis made on the basis of general wave propagation theory for anisotropic layered media. We show that the accuracy of the long-wavelength approximation for nanoscopic anisotropic multilayers is quite satisfactory: if the thickness of a multilayer divided by the wavelength comprises a few hundredths, then the errors of approximate formulas do not exceed a few percent. The most useful feature of obtained approximate expressions is that they are simply invertible, allowing a direct calculation of the parameters of ultrathin layers.