Doppler-Free Two-Photon Cavity Ring-Down Spectroscopy of a Nitrous Oxide (N_2O) Vibrational Overtone Transition [article]

Gang Zhao, D. Michelle Bailey, Adam J. Fleisher, Joseph T. Hodges, and Kevin K. Lehmann
2020 arXiv   pre-print
We report Doppler-free two-photon absorption of N_2O at λ = 4.53 μm, measured by cavity ring-down spectroscopy. High power was achieved by optical self-locking of a quantum cascade laser to a linear resonator of finesse F = 22730, and accurate laser detuning over a 400 MHz range was measured relative to an optical frequency comb. At a sample pressure of p = 0.13 kPa, we report a large two-photon cross-section of σ_13^(2) = 8.0 × 10^-41 cm^4 s molecule^-1 for the Q(18) rovibrational transition at a resonant frequency of ν_0 = 66179400.8 MHz.
arXiv:2003.12624v1 fatcat:oa6j7rf57fbzhi5kieqdtuuame