Definition of laser-induced breakdown spectroscopy

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Photonics Dictionary

laser-induced breakdown spectroscopy: Laser-induced breakdown spectroscopy (LIBS) is an analytical technique that uses a high-powered laser pulse to ablate a small amount of material from a sample, creating a plasma. This plasma emits light, which is analyzed to determine the elemental composition of the sample.

Principle of operation: A focused laser pulse is directed at the sample, causing rapid heating and vaporization of a small amount of material. The vaporized material forms a high-temperature plasma, which consists of excited atoms, ions, and electrons. As the plasma cools, these excited species emit light at characteristic wavelengths corresponding to the elements present in the sample.

Spectral analysis: The emitted light is collected and analyzed using a spectrometer. The spectrum consists of discrete lines corresponding to the atomic emission lines of the elements in the sample. By comparing the observed wavelengths and intensities to known reference spectra, the elemental composition of the sample can be determined.

Advantages:

Minimal sample preparation: LIBS requires little to no sample preparation, making it a quick and straightforward technique.

Real-time analysis: The technique provides immediate results, allowing for real-time analysis and monitoring.

Portability: Portable LIBS systems are available, enabling field analysis in various environments.

Broad elemental range: LIBS can detect a wide range of elements, from light elements like hydrogen to heavy metals.

Applications:

Environmental monitoring: Used for detecting contaminants in soil, water, and air.

Industrial applications: Employed in quality control, material sorting, and process monitoring in industries such as metallurgy and manufacturing.

Archaeology and art conservation: Analyzes the composition of artifacts and artworks without damaging them.

Geology and mining: Determines the composition of minerals and ores in geological samples.

Biomedical: Used for tissue analysis and detecting trace elements in biological samples.

Limitations:

Matrix effects: The presence of other elements and the physical state of the sample can affect the accuracy of the results.

Detection limits: While LIBS can detect a wide range of elements, the sensitivity may vary, and detection limits may not be as low as other techniques like ICP-MS (Inductively Coupled Plasma Mass Spectrometry).

Calibration: Accurate quantitative analysis requires calibration with standards, which can be complex due to matrix effects and varying plasma conditions.

Instrumentation:

Laser: A high-energy pulsed laser, often a Nd:YAG (neodymium-doped yttrium aluminum garnet) laser, is commonly used.

Optics: Lenses and mirrors to focus the laser pulse on the sample and collect the emitted light.

Spectrometer: Analyzes the collected light to produce the emission spectrum.

Detector: A device such as a CCD (charge-coupled device) or photomultiplier tube to detect the light and convert it into an electrical signal for analysis.