What is laser-induced breakdown spectroscopy (LIBS)?
Laser-induced breakdown spectroscopy (LIBS) is a type of atomic emission spectroscopy that employs a laser to ablate or vaporize a microscopic layer of a sample’s surface. The resultant plasma caused by this laser ablation process emits light as it cools. This light is then collected and analyzed with a spectrometer for quantitative and qualitative material analysis.
This rapid chemical analysis technique offers many advantages compared to other elemental analysis techniques:
- A sample preparation-free measurement experience
- Extremely fast measurement time, usually a few seconds, for a single spot analysis
- Broad elemental coverage, including lighter elements, such as H, Be, Li, C, N, O, Na, and Mg
- Versatile sampling protocols that include a fast raster of the sample surface and depth profiling
- Thin-sample analysis without the worry of the substrate interference
LIBS for Material Analysis
This virtually non-destructive spectral analysis method has valuable applications across numerous physical science fields, including identification of defects in glass, distribution of lithium, manganese, nickel, and other elements in lithium-ion batteries, depth analysis of different layers, and brief analysis of the element content in samples.
A typical detection limit of LIBS for heavy metallic elements is in the low-PPM range. LIBS is applicable to a wide range of sample matrices, including metals, semiconductors, glasses, biological tissues, insulators, plastics, soils, plants, soils, thin-paint coating, and electronic materials.
LIBS Analysis Method
LIBS is a type of atomic emission spectroscopy which uses a highly energetic laser pulse as the excitation source. The laser is focused on forming a plasma of the material to be analyzed. Spectral analysis of the plasma emission created yields a fingerprint of the sample’s elemental composition.
LIBS has an exciting analysis method. First, a laser beam is focused on the material’s surface to be analyzed. The temperature reaches 20,000-40,000°C at the focus point. At this point, the material becomes plasma and emits light whose wavelength distribution depends on the material (known as the ‘fingerprint’ of the sample’s elemental composition).
The fiber optics collects the emitted light and enters the spectrometer, which then disperses the light and produces a spectrum according to its wavelength component. The sampled material is analyzed by comparing the sampled scattered light to a given chemical element’s spectrum.
The laser’s typical frequency can generate 300-500 spectra. This enables a complete analysis every three to five minutes, making it a high-speed and reliable analysis method.
For this demanding application, high-speed spectrometers in a multi-channel setup, like the AvaSpec-ULS2048CL-EVO or its smaller version, the AvaSpec-NEXOS, for easy integration into your own system. A collimating lens is often used in LIBS setups to overcome the distance between a sample and the fiber optics.
LIBS in Deep UV / Purged spectrometry
Why purging is needed in deep UV
At wavelengths below roughly 200 nm, and especially below 185 nm, air strongly absorbs UV light, so any open beam path or non‑purged spectrometer will absorb most of the signal before it reaches the detector. Moisture and oxygen also cause scattering and long‑term contamination of optical surfaces, degrading throughput and stability over time. Purging replaces ambient air with an inert, dry gas (typically nitrogen or argon), making the optical path and the spectrometer interior effectively transparent in the deep UV, extending the usable range down to 160 nm.
Purged deep‑UV spectrometers are used for Plasma, LIBS, and Vacuum UV emission spectroscopy, where strong lines below 185 nm are of interest, and a purgeable spectrometer with directly‑attached purgeable optics is used.
Practical considerations for using purged deep‑UV spectrometers
If you plan to use a purged spectrometer for deep UV:
- Gas choice and purity:
Use high‑purity, dry nitrogen or argon; residual O2 and H2O should be reduced to ppm levels for good transmission below ~160–170 nm. - Purge strategy:
Initial high‑flow purge is often needed to displace air, followed by a lower maintenance flow; some systems use a glove box or fully purged enclosure around the optics and sample to maintain low contamination levels. Extra sealing is often required to minimize the leakage rate. - Application:
All products involved need to be useful / optimized to work for the lower wavelengths; the spectrometer is only a part of the solution. - Materials and optics:
Ensure all components in the beam path (windows, lenses, fibers if present) are deep‑UV compatible; standard glass or fibers will cut off too high. - Calibration and stability:
Deep‑UV systems often require careful wavelength and intensity calibration because sources and detectors can age, and small contamination changes have large effects at short wavelengths.
Avantes and purged spectrometry
Avantes offers purged spectrometer solutions tailored to specific applications. Rather than providing standard off-the-shelf configurations, we work closely with customers to design and optimize systems that meet their exact requirements.
Over the years, we have built extensive experience through collaborations with key customers in fields such as LIBS, supporting them in successfully realizing their applications. This approach ensures careful consideration of not only the spectrometer itself, but also the full optical path between the spectrometer entrance and the measurement object (e.g., plasma), as well as proper system calibration.
If you can share more about your application (e.g., wavelength range, transmission vs emission, fiber-coupled or free-space, sample type), our team can help define a configuration and provide usage recommendations tailored to your needs. Click here to contact us!
The images above compare measurements from a non-purged spectrometer (blue) and a purged spectrometer (red). The purged configuration enables detection in the 160–200 nm range, revealing spectral features such as the Carbon line at 165.7 nm. Additionally, the measurement delay can be adjusted to capture different moments in time. In the left image, no delay is applied, so the plasma background is still present. In the right image, a delay is introduced to isolate the LIBS signal after the plasma emission has decayed.
Why choose Avantes for your LIBS application?
- Multi-channel capabilities for high resolution
- Excellent timing and triggering
- Fast and reliable analysis through our spectroscopy software
- Extensive knowledge on LIBS applications
Related Products
These are some of the products mentioned above. Contact one of our sales engineers for advice to find the perfect setup for your specific application.
Application Examples
Below are detailed application notes on various uses of laser-induced breakdown spectroscopy in different applications and industries.