Typical Patterns of Optical Branched Flow

The light is launched into the soap film through an optical fiber.

The optical beam propagates within the thin film, which acts as a slab waveguide with a locally varying thickness.

The light scatters from the thickness variations and forms the pattern of branched flow.

Credit: Patsyk et al, doi: 10.1038/s41586-020-2376-8.