Terahertz imaging has the potential to identify and decipher portions of ancient manuscripts, which may be unreadable at infrared and visible wavelengths. We use a scanning confocal terahertz microscope to scan a medieval parchment with music notes and pentagrams written with different inks. The microscope is based on a continuous-wave solid-state source at 0.3 THz, emitting in the free space with a horn antenna, and a high numerical-aperture ellipsoidal reflector. We present terahertz images with diffraction-limited lateral resolution of approximately 0.5 mm, where the different inks all give similar high contrast. Symbols written on the “verso” side of the parchment, barely glimpsed in the near-infrared photograph, leave a clear imprint in the terahertz images. Artifacts due to imperfect flatness of the parchment are also briefly discussed.
Confocal Terahertz Imaging of Ancient Manuscripts / Flammini, Mariano; Bonsi, Claudia; Ciano, Chiara; Giliberti, Valeria; Pontecorvo, Emanuele; Italia, Paola; Delre, Eugenio; Ortolani, Michele. - In: JOURNAL OF INFRARED, MILLIMETER, AND TERAHERTZ WAVES. - ISSN 1866-6892. - ELETTRONICO. - 38:4(2017), pp. 435-442. [10.1007/s10762-016-0338-x]
Confocal Terahertz Imaging of Ancient Manuscripts
ITALIA, PAOLA MARIA CARMELA;
2017
Abstract
Terahertz imaging has the potential to identify and decipher portions of ancient manuscripts, which may be unreadable at infrared and visible wavelengths. We use a scanning confocal terahertz microscope to scan a medieval parchment with music notes and pentagrams written with different inks. The microscope is based on a continuous-wave solid-state source at 0.3 THz, emitting in the free space with a horn antenna, and a high numerical-aperture ellipsoidal reflector. We present terahertz images with diffraction-limited lateral resolution of approximately 0.5 mm, where the different inks all give similar high contrast. Symbols written on the “verso” side of the parchment, barely glimpsed in the near-infrared photograph, leave a clear imprint in the terahertz images. Artifacts due to imperfect flatness of the parchment are also briefly discussed.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.