A Transformer-Based Approach to Facilitate Inverse Design of Achromatic Metasurfaces

Accurate and efficient prediction of the spectral responses of metasurface unit cells is key to intelligent metasurface design. Here, we propose a Shape-integrated Dual-Spectrum-aware transformer (SiDSaT) for forward prediction of metasurface responses. Trained on a large-scale simulation dataset, SiDSaT achieves a phase mean absolute error (MAE) below 0.05 across both cylindrical and cuboidal unit cells, demonstrating strong prediction accuracy and generalization. We further embedded SiDSaT into an inverse design framework and applied it to the design of single-wavelength and broadband achromatic metalenses. Results of focusing performance and dispersion control confirm the effectiveness and versatility of SiDSaT in supporting the high-precision inverse design of metasurface optical devices. This work offers a scalable and accurate approach for intelligent metasurface design across diverse shape configurations and broadband spectral ranges.