Influence of electrostatic fields and laser-induced discharges on ultrashort laser pulse drilling of copper

We evaluated the application-oriented suitability of electrostatic fields and laser-induced discharges to enhance both debris removal and ablation rate during ultrashort pulse laser drilling of copper. The electric field was varied to either induce or prevent laser-induced electric discharges. Results show that debris is expelled to a much greater distance by applying an electric field. If a laser-induced electric discharge is induced, greater heat-affected zone and greater amounts of debris are observed, pointing to an increased amount of ablated material. Results were independent on the applied voltage polarity, suggesting that there is no significant charge separation in the material plasma.