Visible To Near-Infrared Nearly Perfect Absorption From Alternate Silica And Chromium Layers Deposited By Magnetron Sputtering

We present a novel, to the best of our knowledge, broad-band and angle-insensitive nearly perfect absorber design composed of alternate silica and chromium layers. We show that by depositing a chromium nanofilm on a chromium substrate with a silica spacer, the absorption will significantly enhance from the visible to near-infrared. Then, another silica film is placed on the top of the layered structure as an antireflection coating, resulting in the broadband nearperfect absorption. We fabricate the proposed absorber by magnetron sputtering. The measured results show that our device has an average absorption over 97% in a wide range of wavelengths ranging from 350 to 1170 nm, and its absorption performance exhibits a good angular tolerance up to 50 degrees. The presented absorber design offers a good prospect for large-scale and low-cost manufacturing of absorption-based optoelectronic devices. (C) 2021 Optical Society of America