Papers by Author: Philippe Sciau

Abstract: Optical microscopy allows observation of details of the order of micrometers. In an electron microscope that uses an electron beam to make an image, the resolution is a thousand times better. It becomes possible to observe details of the nanometer (nm) in conventional mode and order of the Angstrom (1 Å = 0.1 nm) in high resolution mode. This technique requires a delicate preparation of samples to be sufficiently thin (≤ 100 nm) to allow the passage of electrons to an observation in transmission. The transfer of energy between incident electrons and atoms in the sample are operated through energy loss spectroscopy (EELS) and X-ray emission (EDX) to perform a chemical analysis of the observed object. The purpose of this paper is to show, through some examples, the potential of transmission electron microscopy and related techniques in the study of structure and composition of heritage materials.

Abstract: Metallic lustre decorations of glazed ceramics, which appeared in Mesopotamia during the 9th century AD, can be considered nowadays as an historical example of controlled nanotechnology for optical devices. Their surprising optical properties are directly due to metallic nanoparticles that Islamic potters were able to bury in the first layers of glaze through empirical chemical means. Lustre technology is fascinating and many papers have been devoted to this subject. Many lustre samples have been investigated with the most modern equipment such as the synchrotron radiation, electron microscopy, micro-Raman spectroscopy and other spectroscopic methods. This decor made in the twelfth century during the Fatimid dynasty shows a quasi-perfect double layer of nanoparticles confirming the high technological mastery of this civilization. Moreover, up to now, no lustre has been found with an organization of nanoparticles as elaborate as the decor presented here.