Photonic quadrupole topological insulator using orbital-induced synthetic flux
Abstract
The rich physical properties of multiatomic crystals are determined, to a significant extent, by the underlying geometry and connectivity of atomic orbitals. The mixing of orbitals with distinct parity representations, such as s and p orbitals, has been shown to be useful for generating systems that require alternating phase patterns, as with the sign of couplings within a lattice. Here we show that by breaking the symmetries of such mixed-orbital lattices, it is possible to generate synthetic magnetic flux threading the lattice. We use this insight to experimentally demonstrate quadrupole topological insulators in two-dimensional photonic lattices, leveraging both s and p orbital-type modes. We confirm the nontrivial quadrupole topology by observing the presence of protected zero-dimensional states, which are spatially confined to the corners, and by confirming that these states sit at mid-gap. Our approach is also applicable to a broader range of time-reversal-invariant synthetic materials that do not allow for tailored connectivity, and in which synthetic fluxes are essential.
Document Details
- Document Type
- Pub Defense Publication
- Publication Date
- Nov 03, 2022
- Source ID
- 10.1038/s41467-022-33894-6
Entities
People
- Gaurav Bahl
- Georg von Freymann
- Jiho Noh
- Julian Schulz
- Wladimir A Benalcazar
Organizations
- German Research Foundation
- Office of Naval Research