Rapid generation of massive thermodynamic datasets using frequency comb spectroscopy.

Area of Science:

• Spectroscopy
• Quantum Optics
• Molecular Physics

Background:

• Accurate spectroscopic parameters are crucial for gas sensing and atmospheric studies.
• Understanding pressure and temperature effects on spectral lines is essential for quantitative analysis.
• Previous studies indicated a lack of vibrational dependence in spectral broadening for acetylene, but a strong rotational dependence.

Purpose of the Study:

• To demonstrate massively parallel spectroscopic measurements of acetylene (12C2H2) using an optical frequency comb.
• To rapidly and simultaneously estimate self-broadening and self-shifting for numerous optical transitions.
• To investigate the pressure- and temperature-mediated broadening and shifting of acetylene spectral lines.

Main Methods:

• Utilized an optical frequency comb for high-resolution, parallel spectroscopic measurements.
• Employed a temperature-controlled sealed gas cell to control and vary pressure and temperature.
• Measured spectral line parameters for 59 optical transitions of acetylene in the 1512–1538 nm range.

Main Results:

• Presented pressure-mediated self-broadening and self-shifting coefficients for 59 acetylene optical lines (v1 + v3 band and hot bands).
• Confirmed the absence of measurable vibrational dependence in spectral broadening across acetylene bands, consistent with prior work.
• Observed a strong dependence of the broadening coefficient on the rotational number.
• Provided extensive measurements of the temperature dependence of self-broadening for each line.

Conclusions:

• Optical frequency combs offer a powerful tool for rapid generation of large spectroscopic datasets.
• The study highlights the significant impact of thermodynamic variations on key spectroscopic parameters of gases like acetylene.
• The findings contribute to improved spectroscopic databases for applications in gas analysis and remote sensing.