Time-resolved plasma properties for double pulsed laser-induced breakdown spectroscopy of silicon

A systematic measurement of plasma properties (temperature, electron number density, pressure) was performed during LIBS of silicon with two nanosecond pulsed lasers operating at 1064 nm. The spectral characteristics of the plasmas were measured to determine the plasma properties as delay time between the laser pulses was changed from 0 to 10 ms. The plasma properties and crater dimensions increased abruptly from 100 to 200 ns. The crater depth increased from 2 to 10 μm (volume increased about 5 times) per pair of double pulses. Enhanced mass removal was indicative of a phase explosion mechanism. Spatial images of plasma emission were measured to study the dynamics of plasma expansion.