Photons in the service of our past: lasers in the preservation of cultural heritage

The study, preservation and restoration of cultural heritage materials and objects are crucial for obtaining important historical information, maintaining their aesthetic appeal or understanding early technologies. The unique, highly diverse character of cultural heritage items impose the need for rigorous scientific approaches, often incorporating non-invasive, mobile or remote technologies and the valorisation of objects and preservation methodologies. Here, we overview the fundamental aspects in the use of lasers for the analysis and restoration of artworks. For the former purpose, emphasis is placed on the use of Raman and Laser-Induced-Breakdown spectroscopies, both of which have been of increasing importance in the field of Cultural Heritage. The use of lasers for the restoration of artworks, in particular of painted artworks and parchments are described. Studies on model polymeric systems, as well as realistic artefacts, have permitted detailed assessment of the mechanisms and of the effects of the procedure. Finally, we provide an assessment of the potential of new laser-based technologies and techniques for the purpose of conservation/restoration of cultural objects.