We measure the absolute frequency of 12 sub-Doppler lines of the P6
and P7 transitions in the 3 band
of 12CH4 using difference-frequency-generation DFG of 1.064-m Nd:YAG
and 1.55-m DFB lasers and a
fiber-based frequency comb referenced to International Atomic Time.
The relative uncertainties are typically
9.410?11, and the determined value for the P7 F2 2 line agrees
with the International Committee for
Weights and Measures recommendation with a discrepancy of 1.28.4
kHz. The combination of the DFG
spectrometer and the frequency comb enables determining energy levels
as accurately as microwave
See references 13 and 14 for other papers that rerference fiber combs.
Mendeley saves you time finding and organizing research
Choose a citation style from the tabs below