Plasma homologous information for assisting laser-induced breakdown spectroscopy: Recent advances in spectral endogenous parameters, acoustic signals, and plasma images

Laser-induced breakdown spectroscopy (LIBS) is hailed as the “future star” of analytical chemistry due to its advantages, including non-contact, in-situ, and online monitoring. However, this technique still faces bottlenecks such as significant matrix effects, high measurement uncertainty, and poor long-term repeatability. Traditional exogenous modulation methods, such as multi-technique integration and laser process optimization, involve relatively complex systems and fail to fully utilize the multidimensional information spontaneously generated during plasma evolution. In recent years, the use of plasma homologous information to assist LIBS detection has become a research hotspot. In this review, we introduce the concept of plasma homologous information, defined broadly as all physical quantities sharing a common origin in the same plasma event. Since this definition is inherently broad, we concentrate specifically on two subsets that can serve to enhance LIBS analysis: (1) spectral endogenous parameters (e.g., internal standard line ratios, plasma temperature, electron density), which are derived directly from LIBS spectra without requiring additional hardware; and (2) multi-channel homologous signals (e.g., acoustic signals, plasma images), which are acquired via independent sensors and provide dynamic and spatial information complementary to the spectrum. We systematically survey the latest advances in how these two categories assist LIBS quantitative and qualitative detection, covering their synchronous acquisition systems, generation mechanisms, core applications, challenges, and future directions. Finally, we summarize the current state of homologous information-assisted LIBS detection and discuss its prospects, aiming to offer readers a clear perspective on the latest cutting-edge developments in this field.