Vortex Light Bullets Guided by Disclination Defects.

The formation of stable spatiotemporal optical solitons carrying vorticity, or vortex light bullets, in a nonlinear medium remains a major challenge due to the possibility of collapse in materials with ubiquitous Kerr nonlinearity and the inherent fragility of vortex-carrying solitons to azimuthal perturbations. Although periodic optical potentials may suppress azimuthal instabilities for certain lattice configurations, vortex light bullets supported by these structures have so far been observed only as transient, weakly unstable objects. Here, we report a new class of stable, thresholdless light bullets carrying vorticity and forming in aperiodic lattices with a focusing cubic nonlinearity. These states can be guided by the disclination defects introduced into Su-Schrieffer-Heeger-like lattices and are thresholdless since they bifurcate from linear disclination modes. Aperiodic disclination lattices considered here may possess different discrete rotational symmetry that in turn determines the allowed values of the topological charge of the vortex bullets. The resulting vortex light bullets can exist in finite spectral gaps and feature wide stability intervals. Our findings show that aperiodic lattices provide rich opportunities for the stabilization of multidimensional states and lead to nontrivial interplay between vorticity and discrete rotational symmetry of the lattice.