Topological Magnetic Lattices for On-Chip Nanoparticle Trapping and Sorting

On-chip optical lattices based on surface plasmon polariton (SPP) fields have been shown to generate diverse novel topologies and potential for sorting nanoparticles. However, the reliance on metallic excitation in SPP systems suffers from heavy ohmic loss and heat buildup. In this work, we propose a magnetic topological lattice based on Bloch surface waves (BSWs) excited on transparent dielectric multilayers, offering ultralong propagation ranges and markedly reduced thermal effects. In contrast to the conventional SPPs, rich topologies appear in the magnetic field and spin vector. Furthermore, large-scale dynamic manipulation as well as size-dependent sorting of nanoparticles is feasible by leveraging the ability to reconfigure lattice topologies via polarization and phase adjustments, which further expands its functional versatility. Our results provide new insight into optical topologies governed by magnetic fields and hold promise for application in other wave systems, including elastic and water waves.