  A detailed analysis of the propagation of laser gaussian beams at critical
angles shows in which conditions it is possible to maximize the breaking of
symmetry in the angular distribution and for which values of the laser
wavelength and beam waist is possible to find an analytic formula for angular
deviations of the Snell law. For propagation throughout $N$ dielectric blocks
and for a full breaking of symmetry, overcoming the well known problem of the
infinity at critical angle, a closed expression for the Goos-Haenchen shift is
obtained. The multiple peaks phenomenon clearly represents an additional
evidence of the breaking of symmetry in the angular distribution of optical
beams. Finally, laser wavelength and beam waist conditions to produce focal
effects in the outgoing beam are also briefly discussed.
