Invertible mapping between structured light and vector terahertz emission
Terahertz (THz) radiation provides a powerful platform for ultrafast spectroscopy, imaging, and communication, yet deterministic control over its spatial and polarization structure remains challenging. Here we establish a unified framework for generating and synthesizing vectorial THz beams through coherent control of ultrafast photocurrents in semiconductors. By exploiting quantum interference between one- and two-photon excitation pathways driven by femtosecond vector beams, we demonstrate that the spatial phase and polarization structure of the optical fields can be directly mapped onto the magnitude and orientation of injected currents. This structured charge motion acts as a programmable THz antenna, enabling tailored far-field emission. Beyond forward modeling of THz generation from cylindrical vector beams and full Poincaré beams, we introduce an inverse-design methodology that reconstructs the required current distribution--and corresponding excitation beam profiles--from a desired THz field pattern. This invertible mapping transforms coherent photocurrent control into a systematic design strategy for THz beam shaping. Our results bridge structured light and THz photonics, providing a route toward compact, all-optical, and reconfigurable THz sources with engineered amplitude, phase, and polarization profiles.