Spark Discharge Assisted Laser-induced Breakdown Spectroscopy

Laser-induced breakdown spectroscopy(LIBS)is a kind of material element analysis technology.It can realize the qualitative analysis and quantitative analysis of the elements to be measured.In recent years,it has been paid more and more attention due to its analysis advantages.The paper introduces the development processes of the technology,and introduces the theoretical basis of the technology from the generation and radiation processes of laser-induced plasmas.At present,the technology has the defect with low detection sensitivity,which hindersthe development of the technology.Based on the technology of spark-discharge assisted LIBS,the paper compares and discusses the differences in the plasma parameters and quantitative analysis accuracy of traditional LIBS and spark-discharge assisted LIBS.Nanosecond laser with a wide pulse width is replaced by femtosecond laser.The ablation mechnisms of the two pulsed lasers are different.The interaction between femtosecond laser and sample is weak,which reduces the influence of continuous background on characteristic spectrum.The action mechanism of femtosecond laser is different from that of nanosecond laser.Using femtosecond laser as excitation light source can reduce the damage to the sample.The experimental results under different voltage and energy conditions are analyzed and compared.The enhancement effect of spark discharge is reflected in the obvious increase of spectral intensity and the extension of plasma life.Combination of spark discharge and nanoparticles assisted laser-induced breakdown spectroscopy has the advantage that it will not pollute the sample.The two enhancement methods produce enhancement effects before plasma production and during plasma expansion.The plasma temperature is calculated by Boltzmann slope and compared with the plasma temperature in the case of traditional LIBS.The plasma temperature is positively correlated with the spectral intensity,indicating that the spectral enhancement effect is obvious when the two enhancement methods are combined.The plasma density is calculated by Stark broadening.The plasma bulk density is related to the ablation quality of the sample,which further proves that the combination of the two enhancement methods will not cause additional damage to the sample.