Terahertz Non-Destructive Thickness Characterization of Optically Thin Scale Layers on Steel

Terahertz imaging is a relatively new technique for nondestructive evaluation. Compared with the destructive micro-cut technique that provides information along the line of cut only, THz imaging nondestructively provides a global mapping of a sample. Hence, this technique has been applied to characterize coated materials and composite laminates. In this work, we characterize optically thin wüstite layers on steel leveraging signal-processing techniques.