Femtosecond Laser Cleaning of Archaeological Cultural Assets

Abstract

This study presents research on femtosecond laser ablation of corrosion crusts from ancient coin. On the surface of ancient coin sample was irradiated with 800 nm laser wavelength, 90 femtosecond laser pulses in duration, and 1 kHz repetition rate. Femtosecond laser ablation was carried out by changing laser intensity using from 1.96 x1013 W/cm2 to 9.82 x 1014 W/cm2 in atmospheric conditions. Scanning electron microscope and optic microscope images were recorded and scanning electron microscope- energy dispersive X-ray spectroscopy graphs and reports were recorded. The used coin belonged to the near Roman Imperial Age where the copper-zinc alloy was used for coins. The amount of copper and zinc ratios before and after application of laser ablation procedure is reported by courtesy of scanning electron microscope-energy dispersive X-ray spectroscopy graphs and reports on surface of coin. Scanning electron microscope and light microscope images show that laser intensities above 9,82 x1014 W/cm2 perform an effective cleaning process.