Spectrally-switchable infrared selective emitters for adaptive camouflage

Abstract

Infrared (IR) camouflage can conceal and disguise weapons, equipment, and installations in infrared regions to minimize the detection or identification. Current researches focus mainly on statical IR camouflage and cannot readily adapt complex application scenes. Herein, we proposed two adaptive IR camouflage emitters, for which the radiation can be changed to adapt various scenes through switching emissivity spectra. The first emitter based on multilayer film is fabricated and demonstrated of possessing two modes 0 and 1. At mode 0, the emitter can achieve IR camouflage and radiative cooling in 5–8 μm (non-atmosphere window). This mode is valuable for improving operation stability between individual and equipment in low-temperature (below 68 °C) environment. At mode 1, the emitter possesses low emissivity in 3–14 μm, which assures thermally-robust IR camouflage in broad temperature range above 68 °C. This emitter is free from ion etching and simple in fabrication, which is prominent for large scale manufacture. To further improve the radiative cooling effect of mode 0 in 5–8 μm, an enhancement emitter is proposed based on metamaterial design. The propagating surface plasmon resonance (PSPR) is utilized to improve maximum emissivity from 0.69 to 0.92 and average emissivity from 0.52 to 0.78 in 5–8 μm at mode 0. The proposed emitters can facilitate development in adaptive IR camouflage, smart skin, and intelligent compatible camouflage device.