Design of a mid-wave infrared computational microspectrometer based on a nanorod-dielectric metasurface.

Metasurfaces have shown great potential in optical imaging and sensing due to their ability to manipulate light fields at the subwavelength scale, especially in spectral detection. In this study, we propose a computational miniature spectrometer operating in the mid-infrared range by integrating a dielectric metasurface with a gold nanopillar array. A genetic algorithm is introduced for the first time, to our knowledge, to select the optimal combination of structures from 726 candidates to construct a filter array. By combining four conventional reconstruction algorithms with a fine-tuning optimization method, high-precision spectral reconstruction is achieved across the 3-5 µm range, with a resolution of 20 nm. This work provides a practical and scalable solution for the miniaturization and integration of mid-infrared spectrometers, offering significant potential for both research and application.