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Updated: Sep 11, 2025
09:40
Measurement and Analysis of Atomic Hydrogen and Diatomic Molecular AlO, C2, CN, and TiO Spectra Following Laser-induced Optical Breakdown
Published on: February 14, 2014
14.3K
Sensing of molecular hydrogen using direct tunable diode laser absorption spectroscopy
Optics Express
|August 13, 2025
Summary
Sensitive measurements of molecular hydrogen (H2) were achieved using tunable diode laser absorption spectroscopy (TDLAS). Accurate quantification requires accounting for collision-induced narrowing and absorption, crucial for H2 sensing.
Area of Science:
- Spectroscopy
- Laser Technology
- Analytical Chemistry
Background:
- Molecular hydrogen (H2) detection is vital for industrial processes and safety.
- Accurate H2 quantification can be challenging due to spectral line complexities.
Purpose of the Study:
- To present sensitive and precise measurements of molecular hydrogen using TDLAS.
- To investigate the S(1) H2 quadrupole transition at 2122 nm and the Q(1) H2 absorption line at 2406 nm.
- To assess the impact of collision-induced narrowing and absorption on H2 measurements.
Main Methods:
- Utilized direct tunable diode laser absorption spectroscopy (TDLAS).
- Employed an 11.4-meter multipass cell for enhanced sensitivity.
- Investigated H2-N2 binary mixtures across a wide concentration range.
Main Results:
- Achieved minimum detectable concentrations of 12 ppmv (1s) and 1.2 ppmv (100s).
- Demonstrated excellent linearity from ppmv levels to pure H2 at 1 atm.
- Observed significant intercollisional dips, particularly for the Q(1) line, impacting high-pressure measurements.
Conclusions:
- TDLAS offers a sensitive and precise method for H2 measurement.
- Accurate H2 quantification necessitates incorporating collision-induced narrowing and absorption effects.
- The findings are critical for advancing H2 sensing in industrial applications.
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