Self-accelerating Topological Photonics

Abstract: Both linear and nonlinear self-accelerating valley Hall edge states are predicted in the composited inversion-symmetry-broken photonic graphene lattice with a domain wall. The linear one that is obtained by superimposing a finite-energy Airy envelope to the valley Hall edge state shows self-accelerating, non-diffracting and self-healing properties, with the accelerating trajectory not exactly a parabola. For the nonlinear one which exhibits well self-accelerating and non-diffracting properties that may turn over the moving direction of the valley Hall edge state, it is constructed by superimposing the self-trapped self-accelerating envelope that is obtained from the envelope equation to the valley Hall edge state. The nonlinear self-accelerating valley Hall edge state can circumvent sharp corners without back-scattering, but it is impossible to completely prohibit radiating into the bulk because the topological protection and the self-accelerating demand contrary length of the oscillating tail. The results exhibit the possibility on manipulating topological edge states via self-accelerating waves, and pave the way for the self-accelerating topological photonics.