Abstract. The usability of pulsed broadband terahertz radiation for the inspection of composite materials from the aeronautics industry is investigated, with the goal of developing a mobile time-domain spectroscopy system that operates in reflection geometry. A wide range of samples based on glass and carbon fiber reinforced plastics with various types of defects is examined using an imaging system; the results are evaluated both in time and frequency domain. The conductivity of carbon fibers prevents penetration of the respective samples but also allows analysis of coatings from the reflected THz pulses. Glass fiber composites are, in principle, transparent for THz radiation, but commonly with significant absorption for wavelengths >1 THz. Depending on depth, matrix material, and size, defects like foreign material inserts, delaminations, or moisture contamination can be visualized. If a defect is not too deep in the sample, its location can be correctly identified from the delay between partial reflections at the surface and the defect itself.

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Abstract. We present the development of a speckle interferometer based on a CO 2 laser and using a thermal infrared camera based on an uncooled microbolometer array. It is intended to be used for monitoring deformations as well as detecting flaws in aeronautical composites, with a smaller sensitivity to displacement compared to an equivalent system using visible (VIS) lasers. Moreover the long wavelength allows working with such interferometers outside the laboratory. A mobile system has been developed on the basis of previous laboratory developments. Then it is validated in a variety of industrial nondestructive testing applications in field working conditions.