Laser-induced breakdown spectroscopy (LIBS) is a versatile analytical tool for studying the elemental composition of any kind of sample, such as solids, liquids, or gases. One of the latest developments in this technique is the ability to use it for elemental imaging, that is to say spatially resolved surface analysis. LIBS imaging is becoming a very attractive and popular technique for the qualitative and/or quantitative spectrochemical characterization of specimens for a wide range of applications. Because of its unique set of intrinsic advantages, LIBS imaging is frequently preferred over competitive and complementary techniques for elemental imaging. This review recapitulates the technical fundamentals of LIBS imaging and focuses on significant applications that have received the most promising attention and have undergone major advances during the last three years in the industrial, geological, and biomedical fields. We also discuss the current limitations that hinder the further development of LIBS imaging, as well as perspectives on the use of LIBS as a part of multimodal imaging strategies, the contribution of chemometrics, and ideas for improving the limits of detection and quantification aspects.

In the past few years, the application of laser-induced breakdown spectroscopy in microscopic elemental imaging has been steadily increasing. The recent improvement in its performance makes this technology more and more attractive for many application fields, including biomedical, geological material analysis, and industry. 1− 5 In LIBS-based imaging, a laser-induced plasma is generated at different locations of a sample with a pattern covering the region of interest. Such a plasma source allows specific optical responses resulting from the relaxation of atoms and ions excited by the high plasma temperature to be elicited. 6, 7 The major advantage of this approach is that it is possible to perform an elemental measurement from a single laser pulse, which simultaneously samples the material (by laser ablation) atomizes and then excites the ablated vapor by heating the plasma. This facilitates unique features of LIBS-based imaging with a series of advantages, including simple instrumentation, operation at ambient pressure and temperature, a fast operating speed (up to kHz), and an all-optical design, fully compatible with conventional optical microscopy. Such compatibility plays a facilitating role in coupling LIBS imaging with other techniques, such as Raman spectroscopy and/or luminescence. In addition to having a table-top instrumentation, LIBS