Laser-induced plasma and laser-induced breakdown spectroscopy (LIBS) in China: The challenge and the opportunity

Laser-induced plasma as a spectroscopic emission source was introduced only two years after the invention of the laser. By focusing a pulse delivered by a ruby laser on the surface of a solid target, Brech and Cross in 1962 first observed optical emission following the laser impact [1], which later had been further identified as the emission from the plasma produced during the laser ablation process of the impacted target. Spectroscopic analysis of the plasma emission immediately demonstrated its huge potential for direct chemical analysis by showing a rich spectrum consisting of specific lines from ions, atoms as well as molecules in the ablation plume The simplicity of the original concept leads to the intrinsic advantages of the analytical technique developed later according to the above mentioned pioneer works and generally called nowadays, laser-induced breakdown spectroscopy (LIBS). The versatility of laser ablation process enables LIBS to directly analyze all kinds of materials, whether solid, liquid or gas. Sampling and excitation by laser pulse together with detection of optical emission are fully compatible with stand-off operation. On the other hand, the ability of a laser beam to be tightly focused provides microanalysis feature of the technique. Last but not least, LIBS shares multiple elemental analysis capability with other analytical techniques based on emission spectroscopy.