title: Experimental Test of Reflectivity Formulas for Turbid Colloids: Beyond the Fresnel Reflection Amplitudes.
abstract: We compare light reflectivity measurements as a function of the angle of incidence for an interface between an optical glass and a turbid suspension of small particles, with theoretical predictions for the coherent reflectance calculated with different available theoretical models. The comparisons are made only in a small range of angles of incidence around the critical angle of the interface between the glass and the matrix of the colloidal suspensions. The experimental setup and its calibration procedure are discussed. We considered two Fresnel-based approximations and another two based on a multiple-scattering approach, and we present results for monodisperse latex colloidal suspensions of polymeric spherical particles in water with particle diameters of 120 and 520 nm, polydisperse titanium dioxide (rutile) particles suspensions in water with a most probable diameter of 404 nm, and suspensions of copper particles in water with diameters of 500 nm. The comparisons between experiment and theory are made without fitting any parameters.
authors.affiliation: Instituto de Fı́sica, Universidad Nacional Autónoma de México , Apartado Postal 20-364, Distrito Federal 01000, México.
authors.forename: Gesuri
authors.initials: G
authors.lastname: Morales-Luna
authors.affiliation: Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México , Apartado Postal 70-186, Distrito Federal 04510, México.
authors.forename: Humberto
authors.initials: H
authors.lastname: Contreras-Tello
authors.affiliation: Centro de Ciencias Aplicadas y Desarrollo Tecnológico, Universidad Nacional Autónoma de México , Apartado Postal 70-186, Distrito Federal 04510, México.
authors.forename: Augusto
authors.initials: A
authors.lastname: García-Valenzuela
authors.affiliation: Instituto de Fı́sica, Universidad Nacional Autónoma de México , Apartado Postal 20-364, Distrito Federal 01000, México.
authors.forename: Rubén G
authors.initials: RG
authors.lastname: Barrera