Fig. 1. Schematic diagram of the proposed metasurface design framework based on only one forward neural network.

Fig. 2. Illustration of the all-silicon meta-atom library. (a) Schematic diagram of meta-atoms for nine classes of silicon pillars. (b) Transmissive amplitude-phase spectra of 5000 randomly sampled meta-atoms of structure types 1 × 1 (top row), 1 × 2 (middle row), and 1 × 3 (bottom row) under x- and y-polarized incidences at frequencies of 0.7 and 1.0 THz, respectively.

Fig. 3. Framework and characterization of the deep learning model. (a) Components and hyperparameters of each layer of the neural network. (b) Training and validation loss curves for three model configurations: base, medium, and large. (c) True and predicted amplitude and phase values for two randomly selected parameter sets from the test dataset.

Fig. 4. Design and characterization results of the designed holographic metasurface. (a) The SEM image of the whole sample and the magnification of the selected area. (b) The intensity and phase of the incident terahertz beams scanned without samples at 1.0 THz. (c) The target, paradigm-optimized, electromagnetically simulated, and experimentally measured results of the hologram for x- (top row) and y-polarizations (bottom row), respectively.

Fig. 5. Design and characterization results of the designed vortex metasurface. (a) Target and paradigm-optimized phases of the metasurface for x- and y-polarizations, respectively. (b) The SEM image of the whole sample and magnification of the selected area. (c) The intensity and phase of terahertz beams scanned without samples at 0.7 THz. (d) The phase and intensity of the xoy plane at z = 8 mm, as well as the intensity of xoz and yoz sections calculated by electromagnetic simulation software for x-polarization (top row) and y-polarization (bottom row), respectively. (e) The phase and intensity of the xoy plane at z = 8.5 mm, as well as the intensity of xoz and yoz sections measured experimentally for x-polarization (top row) and y-polarization (bottom row), respectively.