Measuring the dependence of reflectivity on the incidence angle : a technical note

A simple and easy to implement setup is proposed to be used in undergraduate laboratory classes to study the reflectivity of a material as a function of the incidence angle and, in particular, to investigate Brewster’s law. The apparatus is based on the method used in standard relative specular reflectance spectroscopy measurements: it enables to place the sample and a reference mirror exactly in the same position of the optical path, thus involving only rough alignments and avoiding slow measurements. The setup is tested by measuring the dependence of reflectivity on the incidence angle of a glass plate for s- and p-polarized light.Fundação para a Ciência e a Tecnologia (FCT