Reutilization of nanosecond pulse laser energy and its performance in single particle triggered LIBS
A method that can reutilize the energy of a nanosecond pulse laser beam and its performance in single particle triggered laser induced breakdown spectroscopy (LIBS) were studied. The propagation direction of the laser beam (Nd-YAG laser, 1064 nm, 9 ns and 0–80 mJ) was changed in an appropriate way and the energy overlapped at one point in space. In this setup, the energy used to break down pure air was reduced by 25% and the emission intensity of air plasma improved by 220% under the same pulse energy. Besides, the plasma temperature estimated by the relative line-to-continuum intensity ratio was improved by almost 900 K at 20 mJ. Furthermore, this method was applied in single particle triggered LIBS. NaCl particles with a diameter of ∼10 μm were used as the target sample and the scattered light of an 808 nm continuous laser beam was employed as a trigger signal to trigger the Nd-YAG laser. The emission line intensity of Na element was enhanced by 200%. This method can not only improve the emission intensity of a gas sample but can also be applied to single particle samples and has great significance in the application of ns-LIBS and the research and development of portable LIBS equipment.