Structured light carries its own nontrivial spatial topology. Researchers at Tampere University show that it can be used to engineer the topological properties of matter locally. Driving a topological insulator with an optical skyrmion beam spatially tailors its effective Hamiltonian, producing position-dependent topological gaps and Dirac velocities.

This can create topological and trivial regions separated by optically defined interfaces, without material boundaries or chemical modification, and the shape of these interfaces can be controlled through the light's orbital angular momentum. The work opens a route to dynamically patterning topological phases and to transferring topological characteristics between light and matter. The authors are Matias Mustonen, Ali Moghaddam and Teemu Ojanen of QMAT's Theory of Quantum Matter group, with Marco Ornigotti of Tampere University.

The preprint has not yet been peer reviewed.

Figure: Mustonen et al., arXiv:2610.17181 (2026)