Ablation of metals with femtosecond laser pulses

Abstract

The advantages of femtosecond pulses in laser ablation of materials are well established. With insignificant heat effects to the substrate, femtosecond pulses produce clean precise features on most solid materials without the need for postprocessing. Precision 100 µm holes have been trepanned in materials up to 2 mm thick. The product from surface ablation of materials with femtosecond pulses is expected to be basically a vapor (plasma) without droplets or particles. This absence of droplets or particles that are often associated with longer pulse ablation make femtosecond pulses an ideal candidate for pulse laser deposition to form coatings.This initial study examines the femtosecond pulse ablation of several metals at ambient pressure. In an atmosphere at relatively high pressure, collision of the vapor molecules produced by laser ablation with the gas molecules present is substantially higher than in a vacuum or lower pressures typically used in pulse laser deposition studies. Expansion of the vapor is curtailed and coagulation of the vapor into ultrafine particles are enhanced. The use of a glass slide in close proximity to the vapor produced will induce condensation of the vapor and deposition of the ultrafine particles onto the surface of the slide. The size and structure of these coatings are examined to better understand the efficacy of femtosecond pulse ablation, determine the size of the ultrafine particles produced and verify the absence/presence of droplets.The advantages of femtosecond pulses in laser ablation of materials are well established. With insignificant heat effects to the substrate, femtosecond pulses produce clean precise features on most solid materials without the need for postprocessing. Precision 100 µm holes have been trepanned in materials up to 2 mm thick. The product from surface ablation of materials with femtosecond pulses is expected to be basically a vapor (plasma) without droplets or particles. This absence of droplets or particles that are often associated with longer pulse ablation make femtosecond pulses an ideal candidate for pulse laser deposition to form coatings.This initial study examines the femtosecond pulse ablation of several metals at ambient pressure. In an atmosphere at relatively high pressure, collision of the vapor molecules produced by laser ablation with the gas molecules present is substantially higher than in a vacuum or lower pressures typically used in pulse laser deposition studies. Expansion of the vapor is...