Science Daily bends my head with their report on scientists who’ve tied lasers into knots:
Optical vortices can be created with holograms which direct the flow of light. In this work, the team designed holograms using knot theory — a branch of abstract mathematics inspired by knots that occur in shoelaces and rope. Using these specially designed holograms they were able to create knots in optical vortices.
This new research demonstrates a physical application for a branch of mathematics previously considered completely abstract.