High topological charge lasing in quasicrystals
Kristian Arjas, Jani M. Taskinen, Rebecca Heilmann, Grazia Salerno, Päivi Törmä
Abstract
Photonic modes exhibiting a polarization winding akin to a vortex possess an integer topological charge. Lasing with topological charge 1 or 2 can be realized in periodic lattices of up to six-fold rotational symmetry—higher order charges require symmetries not compatible with any two-dimensional Bravais lattice. Here, we experimentally demonstrate lasing with topological charges as high as −5, +7, −17 and +19 in quasicrystals. We discover rich ordered structures of increasing topological charges in the reciprocal space. Our quasicrystal design utilizes group theory in determining electromagnetic field nodes, where lossy plasmonic nanoparticles are positioned to maximize gain. Our results open a new path for fundamental studies of higher-order topological defects, coherent light beams of high topological charge, and realizations of omni-directional, flat-band-like lasing. Improving information storage with light is necessary for the development of photonic technologies in communications and quantum optics. Here the authors demonstrate lasing from bound states in the continuum with topological charges as high as −5, 7, −17 and 19.