Laser-induced breakdown spectroscopy (LIBS) is an emerging analytical method that has been the focus of substantial research
over the last 25 years. The recent emergence of commercially available LIBS systems from major manufacturers is a sign that
the technology is maturing. This column is the first of a three-part series focusing on major aspects of LIBS. This installment
concentrates on the basics of the measurement and typical implementations. Part II will discuss the choices for LIBS hardware
in detail, in particular lasers and spectrometers, and illustrate the trade-offs between cost, size, and performance. Part
III will discuss LIBS analysis in some depth, exploring the various ways to go from a LIBS spectrum to a solution. Overall,
this column series is intended to provide an overview for those considering implementation of LIBS to solve a particular analytical
problem, and an introduction for those interested in learning more about LIBS.
Laser-induced breakdown spectroscopy (LIBS) has been the subject of a number of recent books (1,2) and numerous review papers
(3–5). Widely referenced charts in the introduction of the Cremers and Radziemski book (1) and the first chapter of Noll's
book (2) illustrate the dramatic increase in the annual number of LIBS papers from near zero through the 1970s to an annual
rate of approximately 300–400 today. As an example, Figure 1 shows the annual rate of papers and patents containing "LIBS"
or "laser-induced breakdown" in their titles from Google Scholar (6). Interestingly, the past few years may indicate a leveling
in the publication rate, and the data can be closely modeled by the following logistic function:
Although it is too early to determine whether the leveling in the rate will be continued, if this trend holds the annual publication
rate would peak around 500 per year, which is the equivalent of about three full monthly journals on an annual basis.
Figure 1: Annual rate of publications and patents containing "LIBS" or "laser-induced breakdown," from Google Scholar. Accessed
August 29, 2013.
Clearly, there has been much progress in the science and application of LIBS. Today we increasingly see LIBS units in corporate
laboratories and even controlling industrial processes. LIBS is deployed to take advantage of a number of positive attributes,
which include minimal sample preparation, particularly compared with methods requiring digestion; speed of analysis; sensitivity
to light elements, particularly compared with X-ray fluorescence (XRF); and "stand-off" ability in which the LIBS system is
removed by distances of anywhere from millimeters to meters from the sample being measured. Because of these advantages there
has been an explosion of interest in LIBS (see Figure 1) over a wide range of applications. However, LIBS is a complicated
measurement, with special considerations related to the sample matrix and working hardware folded into the ablation process
and the analytical laser plasma. Understanding the trade-offs between various component choices in a LIBS system, as well
as the basic hardware arrangements, is key for a successful implementation of LIBS.