Advances in terahertz three-dimensional imaging techniques

Terahertz (THz) waves are characteristic for their low photon energy and fingerprint spectrum and ability to penetrate a large number of nonpolar materials. They have shown many unique advantages in areas such as nondestructive testing, security inspection, biological diagnosis and art identification. Three-dimensional THz tomographic imaging is especially useful for its ability to detect information inside samples. It is becoming a hot research topic and show great promise for future development. In this paper, some typical THz three-dimensional imaging techniques are introduced, along with their basic principles and some potential research advancements. Some existing problems are described and some areas for future development trends are proposed.