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Updated: May 30, 2026

High-speed Continuous-wave Stimulated Brillouin Scattering Spectrometer for Material Analysis
Published on: September 22, 2017
Gas spectroscopy and optical path-length assessment in scattering media using a frequency-modulated continuous-wave
Liang Mei1, Hiran Jayaweera, Patrik Lundin
1Division of Atomic Physics, Department of Physics, Lund University, SE-221 00 Lund, Sweden. liang.mei@fysik.lth.se
Abstract:
Simultaneous assessment of the spectroscopic absorption signal of gas enclosed in a scattering medium and the corresponding optical path length of the probing light is demonstrated using a single setup. Sensitive gas absorption measurements are performed by a tunable diode laser using wavelength-modulation spectroscopy, while the path length is evaluated by the frequency-modulated cw technique commonly used in the field of telecommunication. Proof-of-principle measurements are demonstrated with water vapor as the absorbing gas and using polystyrene foam as an inhomogeneously scattering medium. The combination of these techniques opens up new possibilities for straightforward evaluation of gas presence and exchange in scattering media.

