Phys.org November 11, 2024
Photonic modes exhibiting 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. Researchers in Finland experimentally demonstrated lasing with topological charges as high as −5, +7, −17 and +19 in quasicrystals. They discovered rich ordered structures of increasing topological charges in reciprocal space. Their quasicrystal design utilized group theory in determining electromagnetic field nodes, where lossy plasmonic nanoparticles were positioned to maximize gain. According to the researchers their 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… read more. Open Access TECHNICAL ARTICLE
Quasicrystal design. Credit: Nature Communications volume 15, Article number: 9544 , 5 November 2024Â