title: Quantitative spectrophotometry of scattering media via frequency-domain and constant-intensity measurements.
abstract: The attenuation of light by scattering and absorbing media is nonlinearly dependent upon the absorption coefficient, since detected light has experienced many different flight times. The frequency response of such a sample to modulated light is also nonlinear. We derive an expression for the attenuation that includes both the absorption coefficient and the modulation frequency. Its form is a power series whose coefficients are the cumulants of the temporal point-spread function (TPSF). Recasting this expression in terms of intensity leads to a similar expression with the cumulants replaced by the moments of the TPSF. A means of exploiting this relationship to produce estimates of the absolute concentration of the absorbing species is suggested.
authors.affiliation: Applied Optics Group, School of Electrical and Electronic Engineering, University of Nottingham, UK. john.crowe@nottingham.ac.uk
authors.forename: John
authors.initials: J
authors.lastname: Crowe
authors.forename: David
authors.initials: D
authors.lastname: Morris
authors.forename: Malcolm
authors.initials: M
authors.lastname: Woolfson
authors.forename: Paul
authors.initials: P
authors.lastname: Rodmell
authors.forename: John
authors.initials: J
authors.lastname: Walker