title: Variable-length cell for studies of gas spectra with extremely short optical paths.
abstract: We present a cell for studies of light transmission through very strongly absorbing gases. It uses a fixed window and a mirror, parallel to the latter and attached to a micrometric linear motion feedthrough monitoring mirror-window distances from 0 to a couple of centimeters. This device is tested by recording CO2 gas spectra near 4.3 μm using a Fourier transform spectrometer. Their analysis shows that optical-path lengths between 20 and 2000 μm have been obtained. This now enables spectroscopic measurements of self-broadening coefficients of O16C12O16 lines in the ν3 band, for instance, and opens perspectives for optical soundings of thin films of porous materials.
authors.forename: Sébastien B
authors.initials: SB
authors.lastname: Morales
authors.forename: Edouard
authors.initials: E
authors.lastname: Pangui
authors.forename: Xavier
authors.initials: X
authors.lastname: Landsheere
authors.forename: Ha
authors.initials: H
authors.lastname: Tran
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Hartmann