Parhelic-like circle from light scattering in Plateau borders

• We obtained halo formation from light scattering in a Plateau border using an experiment.
• We explained halo formation using geometrical theory of diffraction.
• An optical element based on a Plateau border is proposed.
• We compared some aspects of the parhelic circle with the parlaseric circle.

We are reporting a new simple optical element to generate halos. We have observed interesting patterns of light scattering in Plateau borders in foams. In analogy to the atmospheric phenomena known as parhelic circle, sun dogs, and sun pillars, we have named the features of the patterns observed as parlaseric circle, laser dogs, and laser pillars. The triangular symmetry of the Plateau borders is analogous to the hexagonal symmetry of ice crystals which produce these atmospheric phenomena. Working with one Plateau border at a time, we have observed wave optics phenomena that are not perceived in the atmospheric phenomena, such as diffraction and interference.