Effective strategy for visible-infrared compatible camouflage: surface graphical one-dimensional photonic crystal

Herein, a novel design concept of a surface graphical photonic crystal (SGPC) has been proposed as an effective strategy to achieve angle-insensitive visible-infrared compatible camouflage. The SGPC, designed as a quasi-periodic Ge/ZnS photonic crystal following an arithmetic sequence in the physical thickness for each period, possesses a functionalized ZnS surface consisting of lithography-fabricated mosaic patterns with various etching depths. Our experiment data demonstrate the excellent infrared camouflage capability of the SGPC with a high average reflectance of 92.7% (surface emissivity ϵ=0.07) in 8-14 μm, and related simulations further reveal the satisfying angle-insensitive reflection characteristic with a maximum effective relative photonic bandgap δ_BW=91.3% in 0°≤θ≤60°. Besides, the irregular mosaic patterns with various etching depths constitute a colorful digital camouflage on the surface of the SGPC, realizing an outstanding optical camouflage capacity without distinct angle dependency (dominant wavelength shift δ_λd=|λ_θ-λ₀|/λ₀≤2.33%).