Absolute CO number densities measured using TALIF in a non-thermal plasma environment

We report first measurements of time-resolved absolute CO number densities and rotational temperatures in a non-thermal CO ₂ plasma environment using TALIF with a nanosecond pulsed laser. Two-photon excitation spectra from the B ¹Σ+(v′ = 0) ← X ¹ Σ+ (v″ = 0) Q-branch are recorded and fitted to extract rotational temperatures. Absolute number densities are determined from the frequency-integrated excitation spectrum. The plasma under investigation is a pulsed glow discharge operated at a frequency of 60 Hz with an plasma-on time of 5 ms per plasma cycle, 50 mA plasma current and a pressure of 6.67 mbar. CO number densities range from (2.6 ± 0.6) × 10 ²² m ^-3 to (1.2 ± 0.3) × 10 ²² m ^-3, while rotational temperatures range from 370 ± 40 K to 700 ± 70 K at the beginning and end of the plasma-on phase, respectively. Our results show fair agreement with literature data.