Plasma-grating-induced breakdown spectroscopy

Laser-induced breakdown spectroscopy (LIBS) is a useful tool for determination of elements in solids, liquids, and gases. For nanosecond LIBS (ns-LIBS), the plasma shielding effect limits its reproducibility, repeatability, and signal-to-noise ratios. Although femtosecond laser filament induced breakdown spectroscopy (FIBS) has no plasma shielding effects, the power density clamping inside the filaments limits the measurement sensitivity. We propose and demonstrate plasma-grating-induced breakdown spectroscopy (GIBS). The technique relies on a plasma excitation source—a plasma grating generated by the interference of two noncollinear femtosecond filaments. We demonstrate that GIBS can overcome the limitations of standard techniques such as ns-LIBS and FIBS. Signal intensity enhancement with GIBS is observed to be greater than 3 times that of FIBS. The matrix effect is also significantly reduced with GIBS, by virtue of the high power and electron density of the plasma grating, demonstrating great potential for analyzing samples with complex matrix.