Structured low-emissivity films with periodic micro-hole arrays for robust specular reflection suppression and background-adaptive infrared camouflage

The rapid advancement of multispectral reconnaissance technologies poses an escalating threat to the survivability of military assets, necessitating the development of sophisticated, compatible camouflage. Although dielectric/metal/dielectric (DMD) stacks such as AZO/Ag/AZO films, offer high visible transparency and low infrared emissivity, their application is hindered by intense specular glints in the visible spectrum and identifiable thermal silhouettes caused by spatially uniform emissivity. Herein, we report a strategy to overcome these limitations by introducing a periodic micro-hole array onto the DMD film surface. By strategically tailoring the hole diameter and array period, we achieve precise modulation of the filling factor, which serves as a dual-functional mechanism for emissivity tuning and reflective energy redistribution. Experimental results demonstrate that this architecture enables an exceptionally wide emissivity tuning range (from 0.05 to 0.83) while effectively suppressing specular reflection via high-order diffraction, all while preserving high visible-light transmittance. As a proof of concept, transparent camouflage films were engineered based on real-world background thermal textures. These films successfully reproduced complex thermal patterns and exhibited superior visual compatibility, highlighting the significant potential of periodic micro-structured DMD films for next-generation multispectral stealth and radiative thermal management.