Reflection of a Gaussian beam from a dielectric slab

The problem of reflection of a Gaussian beam from a parallel-sided dielectric slab is studied from the angular-spectrum point of view. It is shown that the path of the peak of the reflected profile undergoes three types of effects with reference to its expected geometrical path: a lateral displacement independent of the propagation distance, a focal shift, and an angular shift that results in a lateral shift proportional to the total propagation distance between the beam waist and the point of observation and independent of the location in between, where reflection takes place. These effects are illustrated by computer simulating some typical cases. The generality of the analysis and its applicability to many different situations are noted. The results of several authors on related problems are shown to be special cases of the general results. The relevance of the analysis and the results to an interesting series of recent experiments in the microwave region is noted.