Melt ejection from copper target in air in the presence of magnetic field using nanosecond pulsed laser ablation

Abstract

The authors report on the study of the crater generated using a nanosecond laser on a copper target in air in the presence of uniform and nonuniform magnetic fields. The analysis of particles deposited inside and around the crater revealed that the generation of large particles (≥0.68 μm) is due to the melt ejection and instability in the liquid layer. The presence of a nonuniform magnetic field causes an additional drift to molten liquid which in turn increases the Kelvin–Helmholtz instability. The percentage of large particles increased due to the enhancement in the Kelvin–Helmholtz instability and mass ejection. The intensity of copper atomic transitions was enhanced in the presence of a uniform magnetic field compared to a nonuniform magnetic field. This is more likely due to an increase in melt ejected mass in the plasma in the presence of a nonuniform magnetic field which may scatter or absorb laser light which in turn decreases laser–matter interaction. The energy-dispersive x-ray spectroscopy and Raman spectroscopy showed the deposited particles are Cu2O. In the presence of a nonuniform magnetic field, the intensity of Raman Cu2O was enhanced, which is attributed to an increase in the number of Cu2O particles.