title: Complex direct comb spectroscopy with a virtually imaged phased array.
abstract: We demonstrate a simple interferometric technique to directly measure the complex optical transmittance over a large spectral range using a frequency-comb spectrometer based on a virtually imaged phased array. A Michelson interferometer encodes the phase deviations induced by a sample contained in one of its arms into an interferogram image. When combined with an additional image taken from each arm separately, along with a frequency-calibration image, this allows full reconstruction of the sample's optical transfer function. We demonstrate the technique with a vapor cell containing H13C14N, producing transmittance and phase spectra spanning 2.9 THz (∼23  nm) with ∼1 GHz resolution.
authors.forename: Sarah K
authors.initials: SK
authors.lastname: Scholten
authors.forename: James D
authors.initials: JD
authors.lastname: Anstie
authors.forename: Nicolas Bourbeau
authors.initials: NB
authors.lastname: Hébert
authors.forename: Richard T
authors.initials: RT
authors.lastname: White
authors.forename: Jérôme
authors.initials: J
authors.lastname: Genest
authors.forename: Andre N
authors.initials: AN
authors.lastname: Luiten