Inverse Design of Terahertz Nanoresonators through Physics-Informed Machine Learning

The rapid development of 6G communications using terahertz (THz) electromagnetic waves has created a demand for highly sensitive THz nanoresonators capable of detecting these waves. Among the potential candidates, THz nanogap loop arrays show promising characteristics but require significant computational resources for accurate simulation. This requirement arises because their unit cells are 10 times smaller than millimeter wavelengths, with nanogap regions that are 1,000,000 times smaller. To address this challenge, we propose a rapid inverse design method for terahertz nanoresonators using physics-informed machine learning, specifically employing double deep Q-learning combined with an analytical model of the THz nanogap loop array. Through approximately 200,000 iterations in about 39 hours on a middle-level personal computer (CPU: 3.40 GHz, 6 cores, 12 threads, RAM: 16 GB, GPU: NVIDIA GeForce GTX 1050), our approach successfully identifies the optimal structure, resulting in an experimental electric field enhancement of 32,000 at 0.2 THz, 300% stronger than previous achievements. By leveraging our analytical model-based approach, we significantly reduce the computational resources required, providing a viable alternative to the impractical numerical simulation-based inverse design that was previously impractical.