Estimating Complex Refractive Index Using Ellipsometry

Gule Saman, Edwin R. Hancock

Abstract: The paper is about estimating complex refractive index images of surfaces. Complex refractive index allows both the transmission and absorption properties of a surface to be characterised. Although widely used in applied optics, there has been little work on its use in image processing and surface inspection. In this paper we describe how to compute the complex refractive index of a material using simple digital image measurements. Specifically, a novel technique for estimating complex refractive index using ellipsometry is reported. The method uses a simple experimental setup that relies on the use of raw intensity data. This represents an advantage over the methods used in applied optics. Rather than relying on the calibrated measurement of absorption, instead our method relies on measuring the relative change in reflection amplitude which is a dimensionless quantity.