Spectral and plasma characteristics of GaIn liquid metal in LIBS

This study investigates the laser-induced breakdown spectroscopy (LIBS) characteristics of GaIn liquid metal under varying laser energies and time delays. The temporal and spectral behaviors of the plasma were analyzed through measurements of emission intensity, signal-to-noise ratio (SNR), relative standard deviation (RSD), electron temperature (Te), and electron density (Ne). The results show that GaIn generates stable plasma emissions, with RSD values typically below 10% and SNR improving with increased laser energy. Time-resolved analysis reveals that Te ranges from 4000 to 6000 K, while Ne remains comparatively high at 3.0–4.0 × 1017 cm-3. Compared to solid metal targets, the GaIn plasma exhibits lower temperatures but higher electron densities, likely due to differences in energy coupling and expansion behavior associated with the liquid phase. These findings highlight the influence of target state and physical properties on LIBS plasma dynamics and signal characteristics. The results provide a basis for future development of LIBS calibration strategies tailored for liquid metal systems.