CoSP: Reconfigurable Metamaterial Inverse Design via Contrastive Pretrained Large Language Model.

Metamaterials for light manipulation at subwavelength scales face significant design challenges due to their complex and sophisticated structures, leading to the emergence of deep learning as a powerful tool to streamline their design process. However, existing deep learning-based inverse design methods fall short in the design of reconfigurable metamaterials (RMMs), whose optical characteristics switch between different states upon external stimuli. To address this challenge, CoSP, an intelligent inverse design method for RMMs based on a contrastive pretrained large language model (LLM), is proposed. By performing contrastive pretraining on multi-state spectra, a well-trained spectrum encoder is obtained and coupled to a GPT-style decoder trained end-to-end from scratch. Equipped with the preservation of linguistic capabilities, CoSP is capable of describing material structures with target optical properties in natural language. Numerical experiments demonstrate that CoSP can design RMM structures for multi-state, multi-band optical responses, showing great potential in versatile applications such as thermal management, optical computation, and telecommunications.