Abstract
The (30012) ← (00001) band of 12C16O2 in the 1.6 μm region is used for satellite observation of carbon dioxide in the Earth's atmosphere. Here, we report a Doppler-free spectroscopy study of this band with comb-locked wavelength-modulated cavity-enhanced absorption spectroscopy. Frequencies of 18 transitions with the rotational quantum numbers up to 42 were determined with sub-kHz accuracy, corresponding to a fractional uncertainty at the 10-12 level. With this precision, we revealed an anomalous decrease of the line shift and an increase of the line broadening for the Lamb dips of CO2 in the low-pressure regime compared to values obtained from Doppler-limited spectra at higher pressures.
Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
