Fig. 3: Experimental characterization of DVM.
From: Experimental observation of topological Dirac vortex mode in terahertz photonic crystal fibers
a Microscopic images of the 3D-printing PCF cross-section. The coordinate system is defined based on symmetry with the origin at the center of the PCF. Scanning paths along AA and BB are illustrated. b Measured time-domain x-polarized electric field distribution along path AA. c Experimentally reconstructed band structure of the DVM with a corresponding fitting line. The linear band structure exhibits excellent agreement with simulation results. Inset: temporal-spectral distributions obtained by performing STFT at the origin along the dashed path in (b). d Temporal-spatial distributions at 0.3 THz along path AA. The right panel shows the spatial electric field distribution at tw = −0.53 ps, with the dashed line indicating the position where Ex drops to e-1 of its maximum value. e Spatial distributions of the DVM at 0.3 THz
