Pre-heating by defocusation of the CO2-Laser polishing beam: an experimental report from the lab-floor -INVITEDJens Bliedtner, Oliver Faehnle, Anne-Marie Layher, Robin Hassel and Andrea BarzEPJ Web Conf., 255 (2021) 03001DOI: https://doi.org/10.1051/epjconf/202125503001