Laser-induced breakdown spectroscopy: an introduction to the feature issue

摘要

Laser-induced breakdown spectroscopy (LIBS) is an analytical detection technique and sensor technology that is undergoing a dramatic transformation in terms of hardware, software, and application areas. It is a field that is significantly maturing yet at the same time expanding dramatically into new areas. The genesis of laser spark spectrochemistry (the core of the LIBS technique) tracks the development of the laser, as the first pulsed lasers were found to be capable of producing sparks in air and on surfaces. Inevitably, spectral analysis of these laser-induced sparks became an area of study. The current manifestations of this technique aimed toward the purpose of chemical analysis can be traced to the works of Radziemski, Cremers, and colleagues at Los Alamos National Laboratory in the early 1980s. It is from this group that the acronym LIBS first appeared. The thrust and refinement of LIBS as a chemical analytical tool was made possible by continuous advances in component instrumentation, namely the intensified charge-coupled device array detectors and more mature and more reliable laser sources. The array detectors were very important in that they allowed the capture of multiple emission lines from a single LIBS event. In the late 1990s and into the 21st century the field of LIBS entered a new era spurred by developments in component instrumentation, in particular the development of broadband high-resolution spectrometers, including echelle and multispectrometer designs. These important advances have for the first time allowed for the detection of essentially all chemical elements in the periodic table, given the ultraviolet, visible, and infrared emission prevalent in a micro-plasma environment. The asymptotic manifestation of such broadband excitation and spectral analysis is the possibility of LIBS-based sensor technologies capable of the detection and the identification of virtually all forms of matter. Broadband high-resolution spectrometers now enable the simultaneous analysis of multiple key elements of a targeted material. As a result, for the first time it is now possible to identify materials with respect to molecular composition while beginning to look at systems with complex molecular structures, as found in biological materials. In the past few years the possibility of developing LIBS sensors for applications related to homeland security has also emerged. Other notable examples of LIBS progress include the detection of single micrometer-sized particles where the elemental sensitivities are in the low-femtogram range. With attributes such as real-time detection, broad applicability for materials analysis, and no sample preparation, LIBS is transforming into a new and powerful sensor technology for both laboratory and field use. As expected, there has been considerable growth in the commercial availability of LIBS instrumentation.