Multi-species sensing using multi-mode absorption spectroscopy with mid-infrared interband cascade lasers

Area of Science:

• Spectroscopy
• Laser Technology
• Environmental Monitoring

Background:

• Mid-infrared spectroscopy is crucial for chemical analysis.
• Interband cascade lasers (ICLs) offer unique properties for spectroscopic applications.
• Multi-mode absorption spectroscopy (MUMAS) provides a framework for broadband spectral analysis.

Purpose of the Study:

• To report the application of interband cascade lasers (ICLs) to multi-mode absorption spectroscopy (MUMAS) in the mid-infrared region.
• To characterize ICL performance and assess MUMAS capabilities for gas sensing.
• To demonstrate multi-species detection and quantify gas concentrations.

Main Methods:

• Utilized ICLs for mid-infrared spectroscopy.
• Employed MUMAS to record multi-line spectra of gases like methane.
• Calibrated pressure measurements using a capacitance manometer.
• Performed multi-species sensing of methane, acetylene, and formaldehyde mixtures.

Main Results:

• Measured individual ICL mode linewidths between 10-80 MHz.
• Achieved methane pressure measurements with 1.1% uncertainty.
• Demonstrated simultaneous detection of three gases with 10% experimental error for partial pressures.
• Estimated a potential minimum detection limit of ~100 ppmv for MUMAS at atmospheric pressure.

Conclusions:

• ICLs are effective sources for MUMAS in the mid-infrared.
• MUMAS, powered by ICLs, offers precise gas quantification and multi-species detection capabilities.
• The technique shows promise for sensitive environmental monitoring and chemical analysis.