Some comparisons of LIBS measurements using nanosecond and picosecond laser pulses

Laser-induced breakdown spectra were measured by using a 1.3 ps laser pulse on glass, steel, and copper. Material ablation with the use of picosecond excitation is very precise with well-formed sharp-edged craters. The spectra obtained with 570 nm, 1.3 ps excitation decay more quickly and show significantly lower background emission than those that use 1064 nm, similar to7 ns excitation. The background was low enough that excellent laser-induced spectroscopy (LIBS) spectra were obtained on the three samples by using a single 1.3 ps laser pulse and a nongated detector, Similar results were obtained by using nanosecond excitation but with higher relative background signals. The radiance was similar with the use of pico- or nanosecond excitation; however, the radiant intensity was larger with nanosecond excitation because of the larger plasma.