1. Confocal Terahertz Imaging of Ancient Manuscripts
- Author
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M. Flammini, Eugenio DelRe, E. Pontecorvo, Paola Maria Carmela Italia, Michele Ortolani, C. Ciano, Valeria Giliberti, Claudia Bonsi, Flammini, M, Bonsi, C, Ciano, C, Giliberti, V, Pontecorvo, E, Italia, P, Delre, E, Ortolani, M, Flammini, Mariano, Bonsi, Claudia, Ciano, Chiara, Giliberti, Valeria, Pontecorvo, Emanuele, Italia, Paola, Delre, Eugenio, and Ortolani, Michele
- Subjects
Paper ,Microscope ,Schottky diode detector ,Parchment ,Infrared ,Terahertz radiation ,Confocal ,Terahertz ,Condensed Matter Physic ,02 engineering and technology ,Lateral resolution ,01 natural sciences ,law.invention ,Imaging ,010309 optics ,confocal microscope ,Optics ,law ,0103 physical sciences ,Electrical and Electronic Engineering ,terahertz ,Instrumentation ,Physics ,Radiation ,Reflector (photography) ,business.industry ,021001 nanoscience & nanotechnology ,Condensed Matter Physics ,Confocal microscopy ,Horn antenna ,Diffraction limit ,Ink ,0210 nano-technology ,business - 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.
- Published
- 2017