Mid-infrared multi-mode absorption spectroscopy using interband cascade lasers for multi-species sensing

Area of Science:

• Spectroscopy
• Laser technology
• Gas sensing

Background:

• High-speed spectroscopic techniques are crucial for real-time gas analysis.
• Interband cascade lasers (ICLs) offer potential for mid-infrared applications.
• Multimode absorption spectroscopy (MUMAS) requires efficient laser sources and detection methods.

Purpose of the Study:

• To demonstrate the capability of interband cascade laser (ICL) based multimode absorption spectroscopy (MUMAS) for high-speed gas detection.
• To characterize the performance of MUMAS in terms of scan rates and detection limits.
• To assess the simultaneous detection capabilities for multiple gas species.

Main Methods:

• Utilized an interband cascade laser (ICL) operating at 3.7 μm.
• Employed multimode absorption spectroscopy (MUMAS) with scan rates up to 10 kHz.
• Analyzed spectral signatures of hydrogen chloride (HCl) to determine mode linewidths and gas mixtures containing methane, acetylene, and formaldehyde.

Main Results:

• Achieved scan rates of 10 kHz for MUMAS.
• Derived individual mode linewidths of 10-80 MHz from HCl spectra.
• Established a detection level of 30 μbar·m for methane with a 1-second measurement at 100 Hz.
• Demonstrated simultaneous detection of methane, acetylene, and formaldehyde in a mixed gas sample.

Conclusions:

• ICL-based MUMAS is a viable technique for high-speed, sensitive gas detection.
• The method allows for the identification and quantification of multiple gases concurrently.
• MUMAS offers a promising approach for various applications requiring rapid and precise gas analysis.