Numerical study of lateral displacements of Gaussian beams reflected from weakly absorbing media near the Brewster dip and reflected from strongly absorbing media

Using the angular spectrum method, we numerically investigate the reflection of a Gaussian beam reflected from weakly absorbing media near the Brewster dip and from strongly absorbing media. Numerical simulations are presented and the field values are computed as well as the time-averaged power densities. Besides, the number of effective propagation modes is defined. Apart from that, beamsplitting is presented and is interpreted by the missing of the propagation mode when the light is reflected from a weakly absorbing medium near the Brewster dip. Beamsplitting, however, is not observed, therefore both beam shift and angular shift have been calculated when the light is reflected from a strongly absorbing medium. The conditions for Artmann's formula to be valid in the case of the Brewster dip are discussed. Our results do not support the validity of Artmann's formula applied to the case when a Gaussian beam is reflected from weakly absorbing media near the Brewster dip, but indicate that Artmann's formula is valid and very good for the case of a beam reflected from strongly absorbing media.