Comparative investigation of laser-induced breakdown spectroscopy in bulk water using 532- and 1064-nm lasers

The influence of laser wavelength on the characteristics of laser-induced breakdown spectroscopy (LIBS) in bulk water was investigated by using 532- and 1064-nm lasers. We demonstrated that higher laser energy does not lead to higher LIBS signals because of the strong plasma shielding occurring at high laser energies, as shown by the spectroscopic and fast imaging results in this work. At threshold energies of 100% breakdown probability, the 1064 nm beam could induce a plasma with higher electron density and temperature than the 532 nm beam, which leads to higher signal-to-noise ratios and longer lifetimes of the emission lines.