Spatiotemporal Coding Terahertz Plasmonic Vortex on-Chip Interferometer

Plasmonic vortices (PV) stimulated from metallic micro-nano structures hold great promise for improving on-chip data capacity. However, the manipulation freedom degree and reconfigurability of current PV devices still need further development in the terahertz regime, especially the simultaneous excitation of two or more PV modes and their coherent synthesis. In this letter, a terahertz PV interferometer with spatiotemporal coding based on liquid crystal integration is demonstrated, which can dynamically manipulate the transient evolution of spin-orbital angular momentum in the time domain, and the superposition field distribution in the frequency domain. By introducing sufficient surface wave path difference, different modes can be modulated independently within the separated time window based on the liquid crystal encodings. This space-time correlation coding enables to dynamically control the mode weightings, and finally obtains 16 superposition distributions. This reconfigurable on-chip interferometer and its dynamic spatiotemporal regulation mechanism pioneer an avenue for intelligent perception and photon computing.