Upgrade from signal enhancement to plasma modulation for LIBS signal improvement

Abstract

Laser-induced breakdown spectroscopy (LIBS) has emerged as a versatile analytical technique for broad applications in various fields. However, its widespread adoption is severely hindered by challenges in quantitative performance, primarily due to relatively low signal repeatability and matrix effects. These limitations are fundamentally attributed to the drastic spatiotemporal variations of its emission source, the laser-induced plasma (LIP). Currently, signal enhancement is the predominant concept for LIBS signal improvement, but this direction often leads to even lower signal repeatability, a critical factor for LIBS quantification. Originating from the essential understanding of LIBS signal improvement, this work introduces an upgraded concept, plasma modulation, as a paradigm-shifting approach that actively modulates the evolution of the LIP to synergistically optimize signal repeatability and intensity. This work systematically examines the physical mechanisms, evaluates the practical implementations, and assesses the future potential of the plasma modulation methods.