Analysis of gas dispersed in scattering liquids and solids

Summary form only. A preliminary sensitivity analysis shows, that gas signatures should be detectable under many circumstances. We have made preliminary model experiments at 780 nm using diode laser radiation with a sharp spectral imprint due to passage of a cell with rubidium vapour. After passage through several mm of apple tissue or through paper resulting in heavy scattering, the sharp gas feature is clearly visible using two-tone frequency modulation spectroscopy. A set-up for molecular oxygen monitoring at 760 nm using optical fibres for transmission and receiving is being assembled and results will be reported. Numerous applications including medical ones can be envisaged with this hitherto unexplored methodology.