Polaritonic states trapped by topological defects

This paper demonstrates a mechanism to efficiently trap mid-IR structured phonon-polaritons in topological defects of a metasurface integrated with hexagonal boron nitride (hBN). These defects, created by stitching displaced domains of a Kekulé-patterned metasurface, sustain localized polaritonic modes. These 0D higher-order topological modes are imaged in real- and Fourier-space, revealing a singular radiation leakage profile and selective excitation through spin-polarized edge waves. This offers opportunities to control light-matter waves, paving the way for topological polariton shaping, ultrathin structured light sources, and nanoscale thermal management.

Daria Smirnova, Filipp Komissarenko, Anton Vakulenko, Svetlana Kiriushechkina, Ekaterina Smolina, Sriram Guddala, Monica Allen, Jeffery Allen, Andrea Alù, Alexander B. Khanikaev