As the volume of composite parts continues to rise, quality and performance specifications are becoming more and more demanding. In this context, robust and reliable nondestructive testing (NDT) techniques are necessary. Thanks to numerous recent technological breakthroughs in the THz field, the THz technology has proven to be a highly promising technology for composite NDT inspection. In this introductory review, the most relevant aspects of the THz technology as a tool for NDT inspection of composite materials are synthesized and analyzed based on a comprehensive review of the current literature.
To this end, available THz experimental setups are described. Furthermore, THz imaging techniques suitable for composite inspection are analyzed and the THz spectroscopic approach is briefly presented. Finally, a review of the state of the art of THz based composite inspection systems is presented describing and analyzing recent most relevant milestones achieved in the field.
