title: Optomechanical shutter modulated broad-band cavity-enhanced absorption spectroscopy of molecular transients of astrophysical interest.
abstract: We describe a sensitive spectroscopic instrument capable of measuring broad-band absorption spectra through supersonically expanding planar plasma pulses. The instrument utilizes incoherent broad-band cavity-enhanced absorption spectroscopy (IBBCEAS) and incorporates an optomechanical shutter to modulate light from a continuous incoherent light source, enabling measurements of durations as low as ∼400 μs. The plasma expansion is used to mimic conditions in translucent interstellar clouds. The new setup is particularly applicable to test proposed carriers of the diffuse interstellar bands, as it permits swift measurements over a broad spectral range with a resolution comparable to astronomical observations. The sensitivity is estimated to be better than 10 ppm/pass, measured with an effective exposure time of only 1 s.
authors.affiliation: Raymond and Beverly Sackler Laboratory for Astrophysics, Leiden Observatory, University of Leiden , P.O. Box 9513, NL 2300 RA Leiden, The Netherlands.
authors.forename: Anton
authors.initials: A
authors.lastname: Walsh
authors.forename: Dongfeng
authors.initials: D
authors.lastname: Zhao
authors.forename: Wim
authors.initials: W
authors.lastname: Ubachs
authors.forename: Harold
authors.initials: H
authors.lastname: Linnartz