Dual-Band MWIR/LWIR Optical Design for Forest Fire Monitoring

This paper presents a wide-field dual-band infrared remote sensing imaging system for forest fire monitoring and early warning. The system employs a common objective lens design to capture both mid-wave (3–5 μm) and long-wave (8–9.7 μm) infrared information, and utilizes two rows of detector arrays (totaling 2×23) to achieve stitched imaging over a 90° wide field of view. The objective lens adopts a fully symmetric spherical design, ensuring consistent imaging quality across all detector channels. Each detector is preceded by an aspheric refractive-meta surface hybrid lens, which corrects the residual monochromatic and chromatic aberrations from the objective. Through multi-channel joint design and optimization, the system achieves nearly diffraction-limited imaging performance with a large aperture of F/2, providing a ground resolution better than 100 m at an orbital altitude of 500 km.