Laser induced breakdown spectroscopy (LIBS) has existed for nearly as long as the laser itself, with the first systems developed in the 1960s. It has been a fairly rare and marginal technique, but is undergoing a bit of a renaissance as its understanding and acceptance, and laser technology have advanced.

The mechanism underlying LIBS uses atomic emission. When energy excites an atom’s electrons, they emit frequencies of light as they make quantum jumps back to less excited states. Each element has characteristic frequencies, which provide a fingerprint for identification. For LIBS, a laser fires a brief pulse at a sample to provide the energy. The laser vaporizes a small portion of the sample, converting it to plasma. The plasma first emits a continuum of frequencies disguising the signal, but after the initial flash, the atoms in the plasma recombine and emit light, which is captured and analyzed by a spectrometer, providing data on the elements in the sample.

Although LIBS is destructive, the laser removes only a small amount of material, making it suitable for many applications involving solid and liquid samples. LIBS can be used to image a sample, by moving the laser spot, or perform depth analysis, by ablating the same spot with the laser. LIBS is used most commonly in materials analysis of metals and alloys. Here, it competes with techniques such as arc-spark optical emission spectroscopy and X-ray fluorescence (XRF). However, arc-spark generally requires conductive samples, while XRF has difficulty analyzing the lightest elements. LIBS is more versatile and can analyze any element in any sample type. Thus, pharmaceuticals, which are nonconductive and often have lighter organic elements, are common samples. LIBS is also used for environmental samples, polymers, ceramics, forensics and artworks. One intriguing application is in stand-off LIBS: the laser can be directed at a distant object and the flash analyzed remotely. Specialized instruments use stand-off LIBS to test suspected explosives or highly radioactive materials.

Manufacturers of LIBS instrumentation were relatively small companies until recent acquisitions. In May 2012, TSI acquired Photon Machines (see IBO 5/31/12), a strong new market contender. In November 2013, Oxford Instruments acquired RMG Technology (see IBO 11/15/12), which had released a handheld LIBS instrument earlier that year. TSI has also developed a handheld LIBS device (see page 8), as has relative newcomer SciAps (see page 6). These latter two instruments debuted at Pittcon this year. Pharmalaser is the leading LIBS supplier, specialized for pharmaceutical applications. Other suppliers include Applied Spectra, Ocean Optics and Frauenhofer ILT. Applied Photonics and Ameasol are specialized participants in stand-off LIBS detection.

Total market demand for LIBS technology in 2013 was about $10 million, but new product offerings, particularly in handheld LIBS, should help this market grow rapidly in the near term.

LIBS at a Glance:

Leading Suppliers

• Pharmalaser

• TSI

• Applied Spectra

Largest Markets

• Metals/Mining

• Pharmaceuticals

• Environmental

Instrument Cost

• $40,000–$200,000