title: Concentration measurement of gas embedded in scattering media by employing absorption and time-resolved laser spectroscopy.
abstract: Diode-laser-based absorption spectroscopy for the evaluation of embedded gas concentrations in porous materials is demonstrated in measurements of molecular oxygen dispersed throughout scattering polystyrene foam, used here as a generic test material. The mean path length of light scattered in the material is determined with the temporal characteristics of the radiation transmitted through the sample. This combined with sensitive gas-absorption measurements employing wavelength-modulation spectroscopy yields an oxygen concentration in polystyrene foam of 20.4% corresponding to a foam porosity of 98%, which is consistent with manufacturing specifications. This feasibility study opens many possibilities for quantitative measurements by using the method of gas-in-scattering-media absorption spectroscopy.
authors.affiliation: Department of Physics, Lund Institute of Technology, Sweden.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Somesfalean
authors.forename: Mikael
authors.initials: M
authors.lastname: Sjöholm
authors.forename: Janis
authors.initials: J
authors.lastname: Alnis
authors.forename: Claes
authors.initials: C
authors.lastname: af Klinteberg
authors.forename: Stefan
authors.initials: S
authors.lastname: Andersson-Engels
authors.forename: Sune
authors.initials: S
authors.lastname: Svanberg