SUPPLEMENTARY MATERIAL

The supplementary material provides the comprehensive comparison of THz vortex generation methods, an in-depth analysis of the polarization dependence of terahertz (THz) radiation generated through optical rectification (OR), and the transformation from vector vortex to scalar vortex as implemented in this work. It comprises a comparison table, the effective nonlinear coefficient, the definitions and transformations of crystallographic and laboratory coordinate systems, as well as the scalar vortex generation. It also presents the detailed derivation and simulations of THz polarization under the coordinate transformations.