Morphological study of sweat ducts for the investigation of terahertz waves interaction with human skin

Recently it was reported that human sweat ducts play an important role in THz-skin interaction. Further understanding of such effects requires to know the morphological features of these ducts. Here, we analyzed the density and dimension of the ducts based on 3D images obtained with optical coherence tomography. We observed that the ducts possess helical structure and the diameter of the ducts from different regions of the body show considerable resemblance. Based on this information, we numerically determined the resonating frequency of helical ducts in axial mode of operation which resulted in the terahertz frequency region spanning from 0.3 THz to 0.6 THz.