Noninvasive 3D characterization of layered samples using terahertz pulsed imaging and infrared optical coherence tomography

Terahertz pulsed imaging (TPI) and Optical Coherence Tomography (OCT) are two powerful techniques allowing high quality three-dimensional images from within scattering media to be obtained noninvasively. In this paper, we report experimental results of using TPI and OCT for characterizing layered samples including pharmaceutical coatings. We found that infrared OCT provides better axial resolutions whilst TPI is less prone to scattering problems thus is well suited for characterizing pharmaceutical tablet coatings.