title: Design of cavity-enhanced absorption cell for reducing transit-time broadening.
abstract: To reduce the linewidth of Lamb dips, we introduce a cavity-enhanced absorption cell (CEAC) coupled with a Gaussian beam with a 1.9-mm 1/e(2) radius at the beam waist for the reduction of transit-time broadening. We state that transit-time broadening depends only on the beam radius at the beam waist. This fact is useful for the design of the CEAC, and a pair of concave and convex mirrors is thereby employed. We have carried out sub-Doppler resolution spectroscopy of the ν(3) band of CH(4) and the ν(1) band of CH(3)D using a difference-frequency-generation source and the CEAC, and the recorded Lamb dips narrow to 80 kHz (HWHM).
authors.forename: Masashi
authors.initials: M
authors.lastname: Abe
authors.forename: Kana
authors.initials: K
authors.lastname: Iwakuni
authors.forename: Sho
authors.initials: S
authors.lastname: Okubo
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Sasada