A method and device for cleaning surfaces using temporarily coincidental laser pulses of two different wavelengths

摘要

The present invention relates to a method and a device for removal of any kind of superficial encrustation from surfaces, by the synchronous use of the fundamental and one of the harmonic frequencies of a short-pulse laser system (in the order of 1- 40 ns). This is embodied by temporal and spatial overlapping of the two beams in various ratios of energy density values between them. The present invention relates to a problem of major concern, related to the cleaning of stone-sculpted surfaces of historic and/or artistic value without any alteration to the underlying authentic surfaces. The invention can be employed in other materials such as façades, metallic surfaces, glass, paper, wood etc. as well as in other applications of industrial or medical interest, such as the removal of radioactive residues from any type of surfaces or the removal of deposits from any kind of animal tissues. The success of this method is based on the combined action of two discrete mechanisms for the removal of surface deposits, embodied by the use of laser pulses of two different wavelengths simultaneously. The suggested device is based on the spatial and temporal overlapping of the fundamental frequency with one of its harmonics, as well as the possibility to adjust the energy of each one of the two radiations individually.