Deep UV LIBS with Purged Spectrometers

The Challenge with Deep UV LIBS

Many key emission lines for light elements exist below 190 nm—but most systems can’t measure them effectively.

Why?

• Oxygen in air absorbs deep UV wavelengths
• Signal intensity drops dramatically
• Detection becomes unreliable or impossible

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.