Photonic Disclination Nanocavities with Versatile Rotational Symmetries.

Abstract

Disclinations, as real-space topological defects, have been extensively studied across condensed matter and classical wave systems. However, their formation is typically restricted by atomic interaction forces or specific lattice symmetries, severely limiting the tunability. Here, we engineer photonic disclination nanocavities with versatile rotational symmetries through a symmetry-unconstrained Volterra process, surpassing natural system limitations. Through systematic analysis of structural geometry, intercell coupling, and eigenmodes, we reveal that these synthetic disclinations host tightly confined optical states within the photonic bandgap, originating from distinct physical mechanisms. We demonstrate a semiconductor nanocavity laser exhibiting stable single-mode emission across the entire dynamic range, leveraging a high-Q, in-gap disclination state with a near-diffraction-limited mode volume. This work proves that disclination states with diverse discrete symmetries can be rationally designed to achieve exceptional optical confinement. These results open a pathway to design nanophotonic devices with tailored functionalities, positioning disclination defects as a versatile platform for next-generation photonic applications.