Mid-infrared adaptive thermal camouflage using a phase-change material coupled dielectric nanoantenna

Abstract

Recently, camouflage technology has attracted researchers’ attention in a large variety of thermal applications. As a special phase change material (PCM), vanadium dioxide (VO2) is an excellent candidate for the studies conducted on thermal camouflage technology. VO2 has a transition from the insulator phase to the metal phase with the increase of the temperature. With regards to this unique feature, VO2 can contribute dynamic properties to the camouflage design. In this paper, a PCM–dielectric based metamaterial mid-infrared adaptive thermal camouflage nanoantenna is designed to perfectly mimic the atmospheric windows. The adaptive property of the proposed structure is obtained by using an ultrathin VO2 interlayer embedded within the grating. The spectral responses of the structure are computed using the finite difference time domain method, and the invisibility of the structure is proved using power calculations in the different mid-infrared regions.

Diode like high-contrast asymmetric transmission of linearly polarized waves based on plasmon-tunneling effect coupling to electromagnetic radiation modes

“…It is also seen that the guidedmode condition in the dielectric grating waveguide is satisfied, which led to the waveguide-coupled SPP excitation, and then the outcoupling of SPPs to the radiation modes. Moreover, as depicted in figure 3(c), the magnetic field is mainly confined within the grating structure which also shows the formation of the Fabry-Pérot cavity and the excitation of SPPs for the forward illumination [43,44]. Therefore, the overall resonance of the designed structure for the forward illumination is due to the pairing of photonic (Fabry-Pérot) and plasmonic (SRSPP) modes.…”

Flexible Janus Functional Film for Adaptive Thermal Camouflage

“…In general, the targets have higher temperature than the ambient background, so the coatings or films with low emissivity can be effective to hide thermal signals and achieve thermal camouflage. [ 14,15 ] To achieve low emissivity engineering for thermal camouflage, people have proposed the photonic crystal‐based multilayer film, [ 16,17 ] grating nanostructure, [ 18,19 ] nanoparticles‐based materials, [ 20,21 ] functional textiles, [ 22 ] etc. By manipulating the distribution of electromagnetic fields through rational structure design, the photonic crystals can achieve superior low emissivity properties for thermal camouflage.…”

Multi-spectral infrared camouflage through excitation of plasmon-phonon polaritons in a visible-transparent hBN-ITO nanoantenna emitter

“…Thus, in an ideal camouflage compatible radiative cooling scenario, the object should be (i) SWIR absorber, (ii) MWIR and LWIR reflector, (iii) NTIR absorber, and (iv) visible transparent to keep its visual appearance and to minimize solar induced heating. The use of metal-based metamaterial/metasurface nanoantennas is a common approach to acquire suppressed emission in MWIR and LWIR regions while allowing radiative cooling in the NTIR window [4][5][6][7]. However, metallic designs do not meet the transparency and SWIR absorbing requirements.…”