Synthetic Spatiotemporal Plasmonic Vortices on Chip
Phys. Rev. Lett. 136, 256903 – Published 26 June, 2026
DOI: https://doi.org/10.1103/db9j-jc1k
Abstract
Spatiotemporal vortices are polychromatic modes that intertwine orbital angular momentum in space and time. Here, we introduce a new class of such vortices, “spatiotemporal plasmonic vortices,” carrying nontrivial topological spin textures. They are generated by chronotopic interference of temporally delayed plasmonic eigenvortices, where a -phase dislocation in the space-frequency domain maps into a spiraling phase in space-time, with the resulting focus-defocus dynamics emulating U(1) gauge transitions. Using interferometric time-resolved photoemission electron microscopy, we directly image their nanometer-attosecond evolution and control vortex number and position. Quantum-path analysis of coherent two-photon photoemission processes reveals the nonlinear plasmonic polarization fields and angular-momentum conservation, establishing spatiotemporal plasmonic vortices as a platform for probing spatiotemporally structured quantum matter.