High performance infrared selective emissivity film tailored for thermal-stable camouflage

Abstract

A polarization-independent broadband infrared selective absorber/emitter (ISAE) based on multilaminar architecture is proposed and demonstrated. The salient features are that it has both low average emissivity of less than 0.1 in two atmospheric windows (3–5μm and 8–14μm) and otherwise high average emissivity of more than 0.8 in two non-atmospheric windows (2.5–3μm and 5–8μm), which renders it tailored infrared camouflage performance with thermal stability. Meanwhile, there is sharp narrowband absorption around at 10.6μm, which allows it to additionally possess laser camouflage performance. The comprehensive dependence of multispectral selective emissivity properties on the structural parameters, the polarization and incident angle of incoming excitation are analyzed and the underlying physical mechanisms are explored. It is found that the selective absorption/emissivity in band 5–8μm is originated from the fundamental mode plasmonic resonances, while that in 2.5–5μm is originated from the high-order hybrid mode plasmonic resonances therein. Meanwhile, there does exist a coupled competition effect between the hybrid modes in 2.5–3μm and in 3–5μm. All the results construct the basic guideline for designing these kinds of ISAE materials. Furthermore, we reexamine the physical essence of infrared camouflage based on multispectral bands selective emissivity with thermal management and establish an optimized generalized method for evaluating the camouflage performance of ISAE. The proposed ISAE proves to have much better infrared camouflage property throughout 2.5–14μm than the existing designs reported. The proof-of-principle ISAE is prepared and the selective emission spectrum is characterized, which is in good agreement with the simulations.