Optical properties of thin films

Abstract

This chapter first reports expressions for reflection and transmission coefficients for an isotropic thin film on a substrate. It then presents observations regarding the matrix method for layered structures and anisotropic films before presenting an original approach that combines reflection and transmission photoellipsometry for studying a multi-layer structure. The chapter also explores tunable thin films for optical phase and polarization control applications, and provides a theoretical formalism to study them. Although the authors use recent research on VO2 films as a case study, they should note that the same methods and principles would also apply to films made with other tunable materials. Broadly speaking, adjustments on the phase of light leads to two types of effects on light beams: interference effects and polarization effects. Polarization effects rely on relative phase shifts between the orthogonal components of the electromagnetic field.