Estimation for a complex index of refraction based on the Stokes vector of the reflected light under active polarized detection

Abstract

An estimation method for a complex index of refraction based on the Stokes vector of the reflected light under active polarized detection is presented. In this method, the difference of the Stokes vector of the reflected light is used to introduce the three new estimation indices for the L–M nonlinear least squares algorithm to estimate the complex index of refraction n and k of the target, which does not require either interpretation of the diffuse reflection part or calculation of every polarized bidirectional reflection distribution function (pBRDF) matrix element. Aluminum is chosen to be the sample to prove the principle of this method, and the result shows that this method can estimate the complex index of refraction more precisely compared with the Hyde method. The result further shows that the estimation index containing elements related to circular polarization has better performance than the index only containing elements related to linear polarization.