Researches On The Plasma Properties Of Femtosecond Filament Ablared Soil

Heavy metal pollution in soils is a serious problem and harmful for human health.Based on the characteristics of nonlinear and intrinsic physical mechanisms of femtosecond laser plasma,we study on-line detection of femtosecond laser ablation soil plasma properties.In this paper,the effect of pulse energy on the formation of femtosecond filament was studied by using two methods as the fluorescence spectrum and the photographic imaging,and the length and the starting position of the femtosecond filament were obtained.Experiments were conducted to study the effect of femtosecond laser plasma ablation on soil plasma characteristics.The influence of the formation of femtosecond laser plasma pulse energy on the spatiotemporal evolution of soil plasma parameters such as emission spectrum intensity,electron temperature,and electron density was obtained.Based on the light scattering method,the dynamic evolution process of particles ejected by femtosecond laser filament ablation material was obtained.Based on the characteristic study,femtosecond laser and plasma filament inducer spectroscopy was applied to the determination of Pb and Cr in heavy metal elements of soil.The calibration curve and RSD and LOD of Pb elements at different positions of the filaments were obtained.The method called leave-one-out cross validation was used to calculate femtosecond laser plasma filament induced breakdown spectroscopy to measure soil Pb and Cr concentrations and relative errors.Therefore,The results show that FIBS technology is used to detect heavy metal elements in soil with high accuracy,lower RSD and LOD.It provides the experimental basis for online in-situ detection of heavy metal elements in soil by FIBS.