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Molecular dispersion spectroscopy based on Fabry-Perot quantum cascade lasers.
Optics Letters
|January 13, 2017
Summary
This study introduces a rapid dispersion spectroscopy technique using two quantum cascade lasers for analyzing nitrous oxide. The system achieves millisecond acquisition times and high sensitivity for absorption measurements.
Area of Science:
- Spectroscopy
- Quantum Cascade Lasers
- Gas Analysis
Background:
- Dispersion spectroscopy is crucial for analyzing gas properties.
- Traditional methods can be slow, limiting real-time applications.
- Nitrous oxide (N2O) is a significant greenhouse gas requiring precise monitoring.
Purpose of the Study:
- To develop a rapid and sensitive dispersion spectroscopy system.
- To demonstrate its application for low-pressure nitrous oxide analysis.
- To achieve fast acquisition times (<1 ms) for spectroscopic measurements.
Main Methods:
- Utilizing two Fabry-Perot quantum cascade lasers in a differential dual comb setup.
- Implementing active feedback control for simultaneous kilohertz wavelength modulation.
- Performing both absorption and dispersion spectroscopy modes.
Main Results:
- Achieved <1 ms acquisition time for nitrous oxide spectroscopy.
- Demonstrated comparable performance in both absorption and dispersion modes.
- Obtained a noise-equivalent absorption figure of merit in the low 10^-4/Hz range.
Conclusions:
- The developed system offers rapid and sensitive spectroscopic analysis.
- This technique is suitable for real-time monitoring of gases like nitrous oxide.
- The high sensitivity and speed open possibilities for advanced gas sensing applications.
