Scalable manufacturing of metamaterials with multispectral
manipulation
capabilities remains highly challenging, which was generally circumvented
by integrating several single-spectral metamaterials, potentially
leading to complex processes, large thicknesses, and limited fabrication
size. We experimentally demonstrate a standalone and scalable-manufactured
multispectral metamaterial featuring simultaneous visible transmission,
infrared reflection, and microwave absorption. The prepared multispectral
metamaterial with an area of 255 cm2 exhibits a visible
transmittance of 74.5% at wavelengths of 400–700 nm (the highest
80.2% at 510 nm), a thermal emissivity of 0.08 at the infrared (IR)
wavelengths of 2.5–20 μm (the lowest 0.03 at 19.5 μm),
and a microwave absorptance of 63.4% at frequencies of 8.2–12.4
GHz (the near-perfect 97.4% at 11.5 GHz) on average with a deep-subwavelength
thickness of λ/47. The deep-subwavelength multispectral metamaterial
consists of a submillimeter-thick polyethylene terephthalate dielectric
spacer sandwiched by a patterned ultrathin metal and a metal mesh
back-reflector with ultralow sheet resistances. Unlike the conventional
optically transparent microwave absorbers made from indium tin oxides,
the surface plasmonic modes can be excited within the submillimeter-thick
multispectral metamaterial, bringing about the gap plasmon polaritons-induced
microwave attenuation, together with the excellent visible transparency
and high IR reflection/low IR emissivity. This work may inspire the
designs and practical production of standalone multispectral metamaterials
and benefit the protection against ubiquitous IR and microwave reconnaissance
without impeding visual observation.