Intensity of a crossover signal relative to Lamb dips observed in Stark spectroscopy of methane

• Published in: Journal of molecular spectroscopy Vol. 352; pp. 10 - 15
• Main Authors: Okuda, Shoko, Sasada, Hiroyuki
• Format: Journal Article
• Language: English
• Published: Elsevier Inc 01-10-2018
• Subjects: Comb spectroscopy; Crossover resonance; First-order Stark shift; Methane; Mid infrared; Saturated absorption spectroscopy; Methane; Crossover resonance; Comb spectroscopy; First-order Stark shift; Mid infrared; Saturated absorption spectroscopy
• ISSN: 0022-2852; 1096-083X
• DOI: 10.1016/j.jms.2018.07.008

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•Crossover signals are observed in the ν3 band of methane under Stark field.•Intensity of the crossover signal is larger than those of the associated Lamb dips.•The relative intensity agrees well with a rate-equation model in weak saturation.
We have observed twelve triplets of two Lamb dips and a crossover signal in Stark spectroscopy of the ν3 band of methane using a comb-referenced sub-Doppler resolution spectrometer. The crossover signal consists of two crossover resonances in the Λ- and V-type three-level systems, which overlap each other in frequency under the first-order Stark shifts (Tyurikov et al., 1997). The intensity of the crossover signal relative to the Lamb dips agrees well with a simple calculation based on steady-state solutions of rate equations in weak saturation using the observed intensity ratio of the Lamb dips in the Λ-type three-level system.