Single-particle LIBS analysis method for aerosol based on dual-annular beam trapping

Aerosols have significant impacts on human health, ecological environments, and climate change. In situ monitoring of the physical and chemical composition of individual atmospheric aerosol particles is crucial for studying the formation and evolution mechanisms of pollutants, playing a vital role in traceability and precise prevention and control of pollution. Optical trapping technology combined with laser-induced breakdown spectroscopy (LIBS) has emerged in recent years as an effective single-particle analysis method. However, limited by optical trapping efficiency and stability, current approaches still suffer from low analytical efficiency, particularly in analyzing transparent particles. To address this, this study proposes a single-particle analysis method based on "dual-ring optical trapping+LIBS technology". Using a trapping scheme with two counter-propagating horizontal ring-shaped beams, it effectively overcomes the issues of low trapping efficiency and poor stability caused by excessive optical scattering forces in gaseous environments. This setup enables stable trapping of both transparent and light-absorbing particles within the same device, thereby improving the efficiency and universality of single-particle analysis. This method can be widely applied for in situ analysis of single particles in gaseous environments, contributing to research on the formation mechanisms of atmospheric particulate pollutants and pollution traceability.