Chromium-nanostructured Metabsorber for Tunable Color Filtering

Most real-life practical applications continuously use color filters, such as holography, sensing, multicolor displays, imaging, and information encoding, etc. Conventional dye-based transparent color filters face performance degradation due to environmental threats and ultraviolet radiation. The fabrication of nanostructures, meta-devices, and absorbers is getting fast due to well-established and enhanced nanotechnology fabrication techniques. This technological advancement leads toward metamaterial-based polarization-insensitive and sensitive light filtration, which has gained incredible popularity due to its increasing color filtering applications. Here we proposed a chromium (Cr) nanocylinders-based metabsorber for color filtering in the visible spectrum. The proposed metabsorber comprises nine cylindrical bars with a transparent silicon wafer as a substrate and 50 nm thick chromium metal as a ground plane. The total size of the metabsorber is 200 × 200 nm², whereas each cylindrical bar is 40 nm and 60 nm in diameter and height, respectively. Under simulation analysis, the proposed metabsorber depicts almost unity absorption in the visible spectrum for incident electromagnetic waves. In addition, metabsorber have passive-tunability features; specifically, it's absorption varies as the thickness of the substrate changes. Moreover, the metabsorber maintained its high absorption characteristics under large oblique incident angles (≤ 60^o). Hence, relaxed angle tolerance, polarization-insensitivity, and passive-tunability features make the proposed metabsorber an excellent candidate for color filtering in miniaturized imaging/display devices.