Characterizing the reflectance near the Brewster angle: a Padé-approximant approach

We characterize the reflectance peak near the Brewster angle for both an interface between two dielectric media and a single slab. To approach this problem analytically, we approximate the reflectance by a first-order diagonal Padé. In this way, we calculate the width and the skewness of the peak, and we show that although they present a well-resolved maximum they are otherwise not so markedly dependent on the refractive index. As an application of interest, we derive simple expressions for the precision of the Abelès Brewster-angle method.