Femtosecond laser-induced breakdown spectroscopy by multidimensional plasma grating

Plasma-grating-induced breakdown spectroscopy (GIBS) has proven itself superior to filament-induced breakdown spectroscopy (FIBS) in detection of trace elements in soil due to the higher intensity and electron density inside the plasma waveguide. The 2D plasma grating generated by the interference of three non-collinear and non-coplanar femtosecond filaments may become an ideal excitation source for ablation and hence we propose the technique multidimensional-plasma-grating-induced breakdown spectroscopy (MIBS). We demonstrate that MIBS is greatly affected by the laser polarization and inter-pulse delay. The signal intensity with MIBS is observed to be 2 times greater than that of GIBS and the induced plasma lifetime with MIBS has also increased by about 20%. Finally, we demonstrate that the limit of detection (LOD) is reduced from 394.40 ppm for GIBS to 306.47 ppm for MIBS, indicating that MIBS is a promising alternative in detecting trace elements.