An evolutionary algorithm based approach to improve the limits of minimum thickness measurements of multilayered automotive paints

We present a novel numerical approach to decrease the limits of the minimum paint thickness measurements of individual layers in multilayered structures using terahertz pulsed technique in reflection geometry. This method combines the benefits of model-based material parameters extraction, a generalized transfer matrix method, and an evolutionary optimization algorithm. The proposed approach has been successfully applied to resolve individual layer thicknesses down to 5 μm in multilayered automotive paint samples.