Scalable VO-metal metasurface enabling adaptive and frequency-selective infrared switching.

Infrared windows-enabled infrared inspection has significant applications in both civilian and military domains. However, the static and indiscriminate transparency across the visible to infrared regions renders them vulnerable to potential laser damage. In this study, we construct a dynamic infrared optical switch based on a vanadium dioxide (VO)-Al metasurface structure. The phase transition of VO enables dynamic transmittance switching, while the Al metasurface confines this capability to specific wavelengths to mitigate unwanted interferences. The infrared switch transmits light within the 8-14 μm range only in its "ON" state, reflecting other wavelengths across the visible to infrared spectrum. The underlying physics is attributed to plasmon-induced extraordinary optical transmission combined with the reconfigurable metatronic properties of the VO layer. Moreover, while maintaining excellent optical performance, we utilize full-wave simulations to enlarge the feature sizes of the Al metasurface structure to meet the demands for large-area fabrication. This advancement paves the way for practical applications of infrared switches, highlighting significant research implications for intelligent infrared windows and enhancing our understanding of light-matter interactions in reconfigurable photothermal devices.