Dynamics of laser-induced plasma splitting

The dynamics of splitting of the laser-induced plasma plume is investigated by spatiotemporal plasma imaging and spectroscopy. Plasma is induced on a copper target in a broad pressure range (10⁻²–10⁵ Pa) and at varying laser pulse energies (5–40 mJ). Splitting the plume into fast and slow components is observed. The analysis of spatially resolved plasma images and spectra shows that the brightest emission region moves from the slow component to the fast component as time evolves. Copper atoms and ions, which radiate between 315 nm and 335 nm and between 485 nm and 504 nm, belong to the fast component whereas copper atoms, which radiate between 315 nm and 335 nm and between 505 nm and 525 nm, belong to the slow component. A charge separation field is proposed to explain the separation of atoms and ions into the slow and fast components, correspondingly. The results can be of importance for laser induced breakdown spectroscopy, pulsed laser deposition, and nanoscale syntheses.