title: High-resolution terahertz spectroscopy with a single tunable frequency comb.
abstract: We report an improvement of three orders of magnitude in the spectral resolution of a recently proposed single-comb terahertz spectroscopy [Opt. Lett.39, 5669 (2014)]. The improvement is achieved by using a femtosecond optical pulse train with a tunable repetition rate. Terahertz comb with tunable spectral line spacing generated by the train is detected via nonlinear mixing with a harmonic of a CW signal from a microwave frequency synthesizer. By applying this technique to the low-pressure gas spectroscopy, we achieved a 100 kHz spectral resolution in measuring separate absorption lines of the rotational manifold of fluoroform (CF3H).
authors.forename: A S
authors.initials: AS
authors.lastname: Skryl
authors.forename: D G
authors.initials: DG
authors.lastname: Pavelyev
authors.forename: M Y
authors.initials: MY
authors.lastname: Tretyakov
authors.forename: M I
authors.initials: MI
authors.lastname: Bakunov
mesh_terms: D000669:Amplifiers, Electronic; D004867:Equipment Design; D019544:Equipment Failure Analysis; D053844:Lasers, Solid-State; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted / Q000295:instrumentation*; D055068:Terahertz Spectroscopy / Q000295:instrumentation*