Time-resolved characteristics and self-absorption correction of laser-induced plasma in a transient electric field

Transient electric field (TEF) assisted laser-induced plasma (LIP) is a simple, efficient, and low-cost method for plasma spectral enhancement. However, due to the self-absorption effect, the true spectral intensity is reduced, which poses difficulties in the diagnosis of the plasma parameters in the TEF, as well as in the study of the spectral enhancement mechanism. Here, we evaluated and investigated the self-absorption effect in the plasma within the TEF, and corrected it based on doublet lines. Doublet lines intensity ratio, temporal evolutions of plasma parameters, and self-absorption coefficients indicate that the self-absorption effect in LIP-TEF is more severe compared to LIP, which is due to the rapid expansion of LIP-TEF. A self-absorption correction method based on doublet line intensities is developed and applied to LIP and LIP-TEF. It is found that the doublet line intensities increase several times with SA correction on the basis of TEF enhancement. Moreover, the plasma temperature and electron number density are reduced and in agreement with the time-resolved spectra. By virtue of these merits, this study provides not only an approach that can further obtain stronger true emission intensity by self-absorption correction on the basis of discharge enhancement, and also reference results for the plasma parameters before and after SA correction, which contributes valuable insights for plasma diagnostics and promotes the potential applications of LIP.