Determination of the Optical Constants of a Uniaxial Ultrathin Film from FT-IR Spectroscopy

Abstract

To evaluate the optical anisotropy of ultrathin films (d <400 Angstrom), we have developed two calculation procedures which permit us to obtain the complex refractive indexes (n) over tilde(o) and (n) over tilde(e) directly From experimental FT-IR spectra. In the first procedure, two transmission spectra recorded at different angles of incidence are used. The second one requires a transmission spectrum al normal incidence and a normalized differential reflection spectrum (PM-IR-RAS) at grazing incidence. In the present work, these methods have been applied to Langmuir-Blodgett cadmium arachidate monolayers in order to illustrate their possibilities.