High-pulse repetition frequency ultrashort pulse laser processing of copper

This paper presents results obtained in high-pulse repetition frequency ultrashort pulse laser microprocessing of copper. In the study, a variety of ultrashort pulse laser systems supplying high average laser power were applied in order to investigate the influence of the laser parameters on copper ablation. For this, laser pulses of different wavelengths (515 nm, 1030 nm) and pulse durations, ranging between 200 fs and 10 ps, were irradiated to the sample surface by raster scanning of the laser beam. The dependencies of average laser power, pulse energy, and the pulse repetition rate on the ablation rate, the ablation efficiency, and the productivity were studied. A maximum average laser power of 31.7 W was applied in this work. The pulse repetition rate was varied in the rage between 0.2 and 19.3 MHz. Finally, the machining qualities obtained were evaluated by means of surface roughness measurements and scanning electron microscope micrograph analysis.