A spectral standardization method based on plasma image-spectrum fusion to improve the stability of laser-induced breakdown spectroscopy†

Abstract

Laser-induced breakdown spectroscopy (LIBS) faces a notable obstacle in the presence of substantial spectral fluctuations, hindering its progress and prompting researchers to prioritize resolving this complex problem. Considering the circumstances above, a novel methodology referred to as spectral standardization based on plasma image-spectrum fusion (SS-PISF) was introduced. The approach utilizes the valuable information in plasma images and spectra to correct variations in total number density, plasma temperature, and electron number density, resulting in improved spectral stability. To ascertain the efficacy of the SS-PISF method, comprehensive experimental validation is conducted, comparing its performance against the full spectrum normalization method and the simplified spectral standardization method. Experimental tests on aluminum alloy samples demonstrate a remarkable improvement, with the determination coefficient (R²) value of calibration curves increasing by 25.307% after SS-PISF correction. Additionally, the root mean square error of validation (RMSE_V) and standard deviation (STD_V) experience a notable reduction by 28.374% and 2.323%, respectively. For alloy steel samples, the SS-PISF corrected calibration curves exhibit a 14.630% increase in R² and a 17.303% decrease in STD_V. Similarly, for ore pressed samples, the SS-PISF corrected calibration curves witness a 7.031% enhancement in R², alongside a decrease in RMSE_V and STD_V by 21.939% and 4.726%, respectively. These empirical results substantiate the efficacy of the SS-PISF method in significantly improving the spectral stability of LIBS. As a result, SS-PISF holds substantial promise for widespread application in laser-induced breakdown spectroscopy.