Elemental analysis by microwave-assisted laser-induced breakdown spectroscopy: Evaluation on ceramics

A new Laser-Induced Breakdown Spectroscopy (LIBS) enhancement method utilizing interaction between microwave radiation and laser-induced plasma has been evaluated. Experimental parameters such as laser pulse irradiance, microwave duration, and surrounding gas were studied and optimized for the microwave effect through a series of experiments on a piece of alumina ceramic sample. Up to 33 times enhancement on different spectral lines was achieved. Enhancement of the line intensity was found to be at a maximum when the laser ablation was induced at low irradiance on a large area in normal atmosphere. The enhancement was element-dependent and stronger for transitions with low excitation energy. The microwave enhancement in argon atmosphere was not as effective as in air, and the reasons are discussed.