Experimental investigation and modelling of double pulse laser induced plasma spectroscopy under water

In this paper the double pulse laser induced breakdown spectroscopy (LIBS) under water has been investigated both theoretically and experimentally. The laser induced bubble, produced by the first pulse, has been simulated by a theoretical model to clarify the effect of inter-pulse delay on the second pulse LIBS spectrum peculiarities. By experiments and calculations it has been established that the dynamics of the plasma obtained by double pulse LIBS is strongly affected by the chemical reactions between the plasma particles and the background environment inside the bubble which seems to be the main effect in confining the plasma.