Temperature measurement using frequency comb absorption spectroscopy of CO₂

Area of Science:

• Spectroscopy
• Laser Technology
• Physical Chemistry

Background:

• Accurate gas temperature determination is crucial for various industrial and scientific applications.
• Traditional methods for gas thermometry can be complex or limited in scope.
• Carbon dioxide (CO2) is a significant greenhouse gas, making its thermometry relevant for climate studies.

Purpose of the Study:

• To investigate the use of absorption spectroscopy for determining CO2 gas temperature.
• To analyze the effectiveness of a virtually imaged phased array spectrometer in this application.
• To identify measurement and analysis techniques most sensitive to temperature variations.

Main Methods:

• Direct absorption spectroscopy of CO2 using a frequency comb laser.
• Analysis of the gas cell at atmospheric conditions.
• Utilizing a virtually imaged phased array spectrometer for high-resolution spectral analysis.
• Investigating various measurement and analysis techniques.

Main Results:

• Demonstrated the feasibility of using frequency comb laser absorption spectroscopy for CO2 thermometry.
• Identified specific parameters sensitive to gas temperature changes.
• Observed qualitative agreement between experimental trends and theoretical predictions for temperature dependence.

Conclusions:

• Absorption spectroscopy with frequency comb lasers offers a viable method for CO2 gas temperature determination.
• The virtually imaged phased array spectrometer is a suitable tool for such analyses.
• Further refinement of techniques can improve the accuracy and quantitative agreement with theoretical models.