Simultaneous heating and temperature measurements by an infrared laser beam

Area of Science:

• Physical Chemistry
• Laser Spectroscopy
• Gas-Phase Dynamics

Background:

• Accurate temperature measurement is crucial for understanding gas-phase reactions and laser-matter interactions.
• Existing methods for in-situ temperature measurement in laser-induced gas excitation can be complex or indirect.
• Investigating excitation processes in the infrared (IR) region requires precise thermal diagnostics.

Purpose of the Study:

• To propose and validate a novel method for simultaneous heating and temperature measurement of gas absorbers using an IR CO2 laser.
• To investigate the influence of laser intensity, beam radius, and absorber composition on gas temperature.
• To provide an experimental tool for studying IR excitation processes.

Main Methods:

• Utilizing a continuous-wave infrared carbon dioxide (CO2) laser for simultaneous heating and excitation of gas absorbers.
• Measuring gas temperature along the laser beam axis as a function of laser parameters (intensity, radius) and absorber mixture.
• Comparing experimental temperature data with theoretical predictions derived from the absorber's level scheme and physical properties.

Main Results:

• Demonstrated a simple and direct method for laser-induced gas heating and temperature measurement.
• Observed good agreement between experimental temperature measurements and theoretical models.
• Quantified the relationship between laser parameters, absorber properties, and gas temperature.

Conclusions:

• The proposed IR CO2 laser method offers a straightforward and effective approach for simultaneous gas heating and temperature determination.
• The method provides a valuable experimental tool for advancing the understanding of excitation processes in the IR spectral region.
• The validated theoretical model enhances the predictive capability for laser-gas interactions.