Scattering of visible light from silica aerogels

Abstract

Scattering of 633 nm photons from silica aerogels with densities 71, 105 and 143 kg m^-3 is investigated. A polarised He-Ne laser is used as a light source. Two types of data sets are determined: (i) total specific extinction coefficients for the porous specimens and (ii) the scattered intensity as a function of scattering angle theta , with 20 degrees c are in the range 10-25 nm and show a systematic decrease with density. The extinction coefficients E are in the range of 10 m^-1; here no systematic variation of E with density is observed.