Physicists at The University of Tokyo have created a photonic crystal using a unique 13-sided tile known as an einstein. This specific shape, discovered in 2023, solves a long-standing geometry puzzle by covering a surface indefinitely without repeating its pattern.
Researchers used electron beam lithography to etch hundreds of thousands of holes into a silicon nitride chip, arranging them in the einstein tile pattern. When they directed a laser at this structure, the light scattered into a distinct pinwheel formation. The pattern remained consistent regardless of where the beam hit the surface, confirming the structure functions as a stable quasicrystal.
This crystal exhibits a rare property called chirality. Because the individual tile lacks mirror symmetry, the entire structure behaves differently depending on the direction of circular polarization in the incoming light. This response is not possible in standard crystals with repeating grids.
The team believes this behavior could lead to advanced optical computing or communication technologies. By moving beyond traditional repeating patterns, these structures offer new ways to control the movement of light within silicon chips.