Reprogrammable polaritonic skyrmion and meron lattices based on the phase-change material In$_3$SbTe$_2$

Abstract

Optical topological quasiparticles such as skyrmions and merons consist of engineered electromagnetic fields which can be realized via the controlled interference of polaritons. The resulting polaritonic topological lattices offer a promising platform for on-chip information encoding and nanoscale light-matter interaction. However, realizing these functionalities requires active tailoring of the polaritonic topological lattice. Although previous works have achieved tuning of the size of the polaritonic lattice sites, these methods relied on cumbersome and time-consuming fabrication processes and do not allow reconfiguration of the topological invariant. Here, we demonstrate fast optical prototyping of reconfigurable hexagonal and square coupling structures for the generation of polaritonic topological lattices with hyperbolic phonon polaritons in hBN using the phase-change material In$_3$SbTe$_2$. As In$_3$SbTe$_2$ can be switched reversibly between its dielectric ($\varepsilon$>0) amorphous and metallic ($\varepsilon$<0) crystalline phase by laser pulses, metallic In$_3$SbTe$_2$ coupling structures can be optically programmed and reconfigured. Our approach enables tailoring the size of the topological lattice sites by tuning the incident frequency. Moreover, In$_3$SbTe$_2$ allows for tailoring the topological invariant by reprogramming the coupling structure. Our platform enables reprogramming of robust optical topologies within minutes, opening a route toward rewritable on-chip photonic computing based on robust and on demand reconfigurable topological states.