A short introduction to Laser-Induced Breakdown Spectroscopy
Later, Soviet scientists Basov and Prokhorov developed a continuously operatable maser-laser system, for which they shared the 1964 Nobel Prize in physics (Radziemski & Cremers, 2013). In 1958, Shawlow and Townes extended the maser theory to optical frequencies (Schawlow & Townes, 1958). Then, in 1960, Maiman constructed the first working Light Amplification by Stimulated Emission of Radiation, the laser, by using a ruby crystal (Maiman, 1960). In 1964, the Nd:YAG laser, the most commonly used laser in LIBS, was introduced (Cremers & Radziemski, 2006). Further advancements in laser technology expanded the range of lasers used in LIBS applications (Radziemski & Cremers, 2013).
Shortly after the invention of the laser, laser-induced plasma was observed. The first mention of laser-induced plasma as a spectral source was in a meeting abstract by Brech and Cross in 1962 (Brech, 1962). In the following year, Debras-Guédon and Liodec published the first analytical use of laser-induced breakdown spectroscopy (LIBS) for spectrochemical analysis of surfaces (Debras-Guédon & Liodec, 1963). However, it was not until the late 1970s when the LIBS analytical capabilities had started to catch up with other techniques, particularly thanks to the research and development at Los Alamos National Laboratory (Radziemski & Cremers, 2013). LIBS was primarily utilized in industrial applications, e.g. for material differentiation in mining industry or for fossil fuels quality control. LIBS proved to be particularly useful in harsh environments, such as in material differentiation and safety control of nuclear materials or in the analysis of molten glass and metals (Legnaioli), 2020)
Chemometrics, involving statistical and mathematical models for data analysis, was first applied to LIBS in 1994 (Radziemski & Cremers, 2013). The use of LIBS for space exploration and long-range open path analysis was proposed in a 1986 study, envisioning chemical analysis of asteroids and comets from fly-by trajectories (D’Orazio et al., 1968). This study laid the groundwork for later stand-off LIBS instruments, such as the ChemCam instrument on NASA’s Mars rover “Curiosity” (Wiens, 2012).
LIBS has numerous applications across various fields, including environmental monitoring, geological analysis, forensic science, material science and biomedical engineering. It offers several advantages such as rapid analysis, minimal sample preparation, and the ability to analyze samples in situ or remotely.
How it works
The fundamental principle of LIBS involves a high-energy laser pulse used as an energy source for ablation of atoms in the sample. The sample is vaporized into a short-lived, high-temperature plasma, with high enough temperatures to excite electrons to higher orbitals. As the plasma quickly cools down, the excited electrons fall back to lower energy levels, emitting photons with wavelengths proportional to the energy difference between the excited and base orbitals. Each element has a unique electron configuration, thus producing a unique signal, or fingerprint, of emitted photons. The emitted photons are collected and transmitted to a spectrometer and translated to a LIBS spectrum.
References
Brech, F. J. A. S. (1962). Optical microemission stimulated by a ruby laser. Appl. Spectrosc., 16(2), 59.
Debras-Guédon, J., & Liodec, N. (1963). De l’utilisation du faisceau d’un amplificateur a ondes lumineuses par émission induite de rayonnement (laser à rubis), comme source énergétique pour l’excitation des spectres d’émission des éléments. CR Acad. Sci, 257, 3336.
D’Orazio, M., Feigl, P., Grix, R., von Hoerner, H., Krueger, F. R., Li, G., … & Wollnik, H. (1986). Facility for Remote Analysis of Small Bodies FRAS, Parts I and II. Von Hoerner and Sulger Electronics GmbH, Schwetzingen, Germany.
Einstein, A. (1917). Zur quantentheorie der strahlung. Phys Zeit, 18, 121.
Maiman, T. H. (1960). Stimulated optical radiation in ruby.
Radziemski, L., & Cremers, D. (2013). A brief history of laser-induced breakdown spectroscopy: from the concept of atoms to LIBS 2012. Spectrochimica Acta Part B: Atomic Spectroscopy, 87, 3-10.
Schawlow, A. L., & Townes, C. H. (1958). Infrared and optical masers. Physical review, 112(6), 1940.
S. Legnaioli, B. Campanella, F. Poggialini, S. Pagnotta, M.A. Harith, Z.A. Abdel-Salam, V. Palleschi, Industrial applications of laser-induced breakdown spectroscopy: a review, Analytical Methods 12 (2020) 1014–1029. https://doi.org/10.1039/C9AY02728A.
Wiens, R.C., Maurice, S., Barraclough, B. et al. The ChemCam Instrument Suite on the Mars Science Laboratory (MSL) Rover: Body Unit and Combined System Tests. Space Sci Rev 170, 167–227 (2012). https://doi.org/10.1007/s11214-012-9902-4
Cremers, D. A., & Radziemski, L. J. (2006). Handbook of Laser-Induced Breakdown Spectroscopy. Wiley. 10.1002/0470093013
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