Quasiperiodic Light

Laszlo Frazer of Monash University delivered a talk titled "Quasiperiodic Light."

Abstract

Quasiperiodicity is a form of spatial order which is observed in quasicrystalline matter. We construct a quasicrystalline metasurface out of a light emitting diode. Using near-field scanning optical microscopy, we directly image the light field at the surface of the diode in three dimensions with superresolution. The reciprocal space representations of the images show that the light field is quasiperiodic. The quasiperiodic lattice constant evolves to a subharmonic in the evanescent field above the surface. We explain the structure of the light field with wave superposition theory. Periodic ordering is limited to at most 6-fold symmetry. The light field exhibits 12-fold quasisymmetry, demonstrating order while disproving periodicity.