Outlook and developments

Terahertz radiation for the analysis of cultural heritage materials

Figure 1 - Frequency-dependent applications of electromagnetic waves

Figure 2 - Image of a graphite butterfly under 5 mm of plaster [12].

Figure 3 - Stratigraphic cross-section of an easel painting and penetration depth of various electromagnetic waves

Figure 5 - (a) THz TDS signal measured in the time domain, (b) Fourier transform giving access to frequency components

Figure 6 - TDS for reflection applications: study of the various interfaces of a multilayer object in a single, non-intrusive measurement, using photon time-of-flight analysis.

Figure 7 - THz spectroscopy (reflection) of white and red pigments. Inset: visible-light photograph of pigments and corresponding THz TDS image [20].

Figure 8 - THz TDS images of a one-euro coin using different representation modes

Figure 9 - Numerical aperture of a converging lens

Figure 10 - THz TDS imaging of a five-yen coin between two layers of clay

Figure 11 - 3D THz TDS image obtained by superimposing two sheets of papyrus inscribed with carbon black ink

Figure 12 - Image obtained by virtually unrolling a sheet of paper containing a cross drawn with a graphite pencil.

Figure 17 - Visualization of a projection ...

Figure 18 - Diagram illustrating the 3D reconstruction procedure using the BFP algorithm

Figure 19 - (a) Photograph of a quartz cuvette and position of the horizontal section to be visualized with the THz beam, (b) corresponding sinogram, (c) final image of the horizontal section.

Figure 20 - 3D imaging of a Russian doll with the THz scanner

Figure 21 - (a) Photograph of a fish sarcophagus (Ancient Egypt, inventory number 8599), (b) THz image, (c) intensity profile (absorbance) along the red line.

Figure 23 - (a) THz image of pottery in inverted position (Ancient Egypt, inventory number 8608). Markers 1 to 9 indicate the positions of the axial sections visible in (b). Image size: ...

Figure 24 - 3D imaging of pottery in inverted position (Ancient Egypt, inventory number 8608)

Figure 25 - (a) Photograph of a Butti fetish statuette (Teke, Congo), (b) THz transmission image, (c) X-ray radiograph

Figure 26 - (a) Photograph of a talisman horn (sub-Saharan Africa), (b) THz transmission image, (c) X-ray radiograph

Figure 27 - (a) Photograph of an old violin (XIXe century), (b) THz transmission image, (c) X-ray radiography