Attenuated total reflection method for obtaining optical constants of powders

Abstract : An apparatus designed to measure the optical constants of a powder suspended in a liquid is described. A laser source (3.391 m) and attenuated total reflection approach are used. The accuracy of the apparatus is evaluated by comparing measured results for a liquid hydrocarbon to published results from specular reflection measurements. The applicability of the Maxwell-Garnett effective medium theory is considered. Keywords include: Optical constants; Laser; Carbon black; Attenuated total reflectance; Effective medium; Complex permittivity; Infrared; Maxwell-Garnett theory; Complex refractive index.