PhoHS group has developed an innovative, transportable ns Nd: YAG system with triple-wavelength (3λ) beam output. PAλλAS is a deliverable of the CALLOS -project and has been developed at the Institute of Electronic Structure and Laser of FORTH by the Photonics for Heritage Science Researchers, in collaboration with the conservators of EACA to meet the analytical challenges commonly encountered on Athenian monuments.

The 3λ prototype is capable of operating at three wavelengths simultaneously (infrared at 1064nm, visible at 523nm, and ultraviolet at 355nm) and can remove efficiently thick pollution accumulations, or and biological crust in a controlled and safe way for both the object and the operator. Combining two wavelengths, every time, ensures that no damaging or discoloration phenomena occur on the original substrate while revealing its unique ancient surface.

The PAλλAS laser cleaning system is one of the main innovative instruments operating in the open-to-the-public conservation laboratory located in the center of the city of Athens at the premises of the Ephorate of Antiquities of Athens (EAA).

The Project CALLOS «Conservation of Athens antiquities with Laser and Lidar Technologies Open to Science and Public» (CALLOS) operates in the frame of the Special Action “OPEN INNOVATION IN CULTURE” and is co-funded by the European Regional Development Fund (ERDF) and national resources through the Operational Program “Competitiveness, Entrepreneurship & Innovation” (NSRF -EPAnEK) (project code MIS- 5056208).