Temporal Evolution of Polarization Resolved Laser-Induced Breakdown Spectroscopy of Cu

Polarization-resolved laser-induced breakdown spectroscopy based on a temporal investigation of polarized Cu plasma emission is presented by a gated detector with a width of 10 ns and a delay time range of 10 ns–2 µs. Polarization-resolved spectra show that the delay time plays a crucial role in plasma polarization for both continuum and discrete emissions. The polarization degree of continuum emission is shown to be stronger than the polarization degree of discrete emissions at delay times less than 500 ns, while this trend is inverse in a delay time range of 750 ns–1 µs. The mechanism for polarized continuum emission is proposed to have dynamic polarizability of a core, while the polarized discrete emission is driven by the interaction of the plasma with the surrounding environment. The latter may lead either to a deviation of plasma from local thermodynamic equilibrium or generation of self-magnetic fields.