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Simultaneously tuning light absorption wavelength and absorbance is a critical challenge in photoelectric detection, mimic of photosynthesis, and simulation of photoreceptors in some animals' retinas. Here, highly ordered hexagonal nanostructured Si arrays are fabricated using monolayer colloid crystal templates. A quantitative relationship between geometric size and light absorption is unveiled in the Si arrays, namely double‐quarter‐wavelength resonance (DQWR). Based on the DQWR model, the absorption wavelength can be readily tuned from 200 to 2400 nm, and the absorbance can be enhanced from ≈80% to above 99% in the full spectrum. Due to the hemisphere‐shell structural feature of the Si arrays, excellent omnidirectional antireflective performance can also be realized. Most importantly, the outstanding antireflection performance of the nanostructures is independent of the substrate. The results not only have important implications for understanding the antireflective mechanism of the nanostructured arrays, but also endow the approach promising in diverse applications, including biomimicry, antireflective film, infrared imagery, and other optoelectronic devices. [ABSTRACT FROM AUTHOR]

With the development of micro-nano optical technology, the fine and effective regulation of the optical properties of nano-arrays by adjusting their structures, sizes and morphologies has become a new research hotspot. In this work, a series of FeGa micro-nano spherical shell arrays with different diameters and thicknesses on polystyrene spheres (PS) templates using magnetron sputtering is synthesized. By applying an external magnetic field perpendicular to the FeGa arrays and adjusting its intensity, the efficient and reversible control of the intensities and positions of light peaks in the optical absorption spectra of the arrays is realized. Among them, the regulation of light absorption can reach ∼15%. Furthermore, the experimental results are in good agreement with the numerical simulation of the multi-physical field coupling analysis. These results will provide a method to control light absorption and contribute to the research and development of emerging optical devices. By adjusting the vertical external magnetic field, the intensities and positions of light peaks in the optical absorption spectra of the FeGa array can be adjusted reversibly and controllably. [Display omitted] • FeGa arrays have been successfully prepared by a combination of colloidal crystal templates and magnetron sputtering. • Adjusting the intensity of vertical external magnetic field can control the light absorption of FeGa arrays reversibly. • The modulation of light absorptivity can reach ∼15%. [ABSTRACT FROM AUTHOR]