Propagation of Terahertz Radiation in Porous Polymer and Ceramic Materials

Applications of Terahertz Spectroscopy in the Field of Construction and Building Materials

“…Thus, THz technology appears to be useful for characterizing dielectric material properties (23), superstructures (13), voids (22,31,41), inclusions (22,42), defects (22,25,27), glass transition (43), and material aging processes (11). Moreover, the wavelength of THz radiation is comparable to foam cell size (14,21) and additives or fillers (22,23).…”

“…In order to achieve better controlled porosity of ceramics, NDT techniques are needed. Dodson et al (14) used THz technology to find the connection between the structure of porous alumina ceramics and optical properties at THz frequencies. In many applications this material is used for insulation purposes and has excellent durability over a long period of time.…”

“…In many applications this material is used for insulation purposes and has excellent durability over a long period of time. Based on the measurements of optical constants and the different formations of pore size and thickness it was demonstrated that ceramic samples with low porosity have an index of refraction near 1.2, whereas higher porosity ceramics have indices that vary across the THz frequency range (14).…”

“…Currently, different NDT methods (14) are used to analyze construction and building materials, among which the most used are visual methods by means of microscopy and digital camera, ultrasound methods, and acoustic imaging through detecting changes in acoustic attenuation and acoustic signature, as well as IR thermography, where the variation in temperature is recorded as a consequence of heat diffusion and cooling at the material surface. Other methods, involving ionizing radiation, are X-ray computed tomography and neutron tomography.…”

“…More recently, research in the field of THz technology is also focusing on the exploration of building materials. There are some research studies focused on detecting and analyzing material thicknesses and density (12)(13)(14)(15)(16), water absorption (17)(18)(19), optical constants (20)(21)(22)(23)(24), voids and delaminations (18,22,25), inclusions (22), mechanical defects (26,27), material aging (11), weld joints and adhesion (12,18,28), as well as process control (29)(30)(31). A small number of literature references show that the construction and building industry lags behind other sectors in THz applications.…”