Absorption path extension tunable diode laser absorption spectroscopy system with a dual fiber loop configuration

Area of Science:

• Spectroscopy
• Optical Engineering
• Gas Sensing

Background:

• Improving signal-to-noise ratio in infrared gas absorption spectroscopy is crucial for sensitive detection.
• Lengthening the absorption path is a primary method, but faces limitations like optical alignment challenges and interference effects in conventional cells.

Purpose of the Study:

• To develop a novel method for significantly extending the effective absorption path length in tunable diode laser absorption spectroscopy (TDLAS).
• To overcome the limitations of traditional multipass cells for enhanced gas analysis.

Main Methods:

• A modified tunable diode laser absorption spectroscopy (TDLAS) system was designed incorporating a dual fiber loop configuration.
• A theoretical model was established to describe the extended absorption path.
• Experimental verification of the proposed system's effectiveness was conducted.

Main Results:

• The dual fiber loop configuration successfully extended the effective absorption path length of the multipass cell by several times.
• The system demonstrated improved signal-to-noise ratio compared to conventional setups.
• The theoretical model accurately predicted the experimental outcomes.

Conclusions:

• The proposed dual fiber loop configuration offers an effective strategy to significantly enhance the absorption path length in TDLAS.
• This advancement provides a pathway to achieve higher sensitivity and better signal-to-noise ratios in gas spectroscopy applications.
• The method overcomes practical limitations associated with traditional optical path extension techniques.