Spectroscopy of the methane Ņ3 Band with an accurate midinfrared coherent dual-comb spectrometer
Esther Baumann, Fabrizio R. Giorgetta, William C. Swann, Alexander M. Zolot, Ian R. Coddington, Nathan R. Newbury
We demonstrate a high-accuracy dual-comb spectrometer centered at 3.4 υm. The amplitude and phase spectra of the P,, Q, and partial R branches of the methane Ņ3 band are measured at 25 to 100 MHz point spacing with resolution under 10 kHz and a signal-to-noise ratio of up to 3500. A fit of the absorbance and phase spectra yields the center frequency of 132 rovibrational lines. The systematic uncertainty is estimated to be 300 kHz, which is 10-3 of the Doppler width and a 10-fold improvement over Fourier transform spectroscopy. These data quantify the accuracy and resolution achievable with direct comb spectroscopy in the midinfrared.
, Giorgetta, F.
, Swann, W.
, Zolot, A.
, Coddington, I.
and Newbury, N.
Spectroscopy of the methane Ņ3 Band with an accurate midinfrared coherent dual-comb spectrometer, Physical Review Letters
(Accessed June 6, 2023)