Optical Absorption in Nanostructured Materials

Optical absorption in nanostructured materials exploits tailored morphologies and resonant effects at the nanoscale to convert incident light into other forms of energy with high efficiency. By engineering features such as nanopores, metasurfaces, plasmonic cavities or carbon-based microfibres, researchers can achieve broadband, angle- and polarization-independent absorption spanning the ultraviolet to the mid-infrared. Such advances rest on interplay between material composition (metals, dielectrics, semiconductors, carbon allotropes) and structural parameters (periodicity, feature size, aspect ratio), which together control light trapping via mechanisms including surface-plasmon resonances, Mie scattering and effective medium behaviour. These engineered absorbers underpin applications in photovoltaics, photodetectors, thermophotovoltaics, thermal management, stealth technology and Earth observation, with an emphasis on scalable, low-cost fabrication and environmental sustainability.

Research from Nature Portfolio

Recent studies have demonstrated that natural wood can be transformed into mechanically robust superblack surfaces by combining top-down delignification with high-temperature carbonisation. The resulting vertically aligned carbon microfibre arrays display subwavelength cell structures and achieve reflectance below 0.4% across the visible spectrum, independent of incidence angle. In parallel, the incorporation of aluminium dopants into silicon films has been shown to promote the spontaneous formation of nanocone-like microstructures. These microstructured Si–Al films exhibit average absorption exceeding 99% from 350 nm to 2 µm over wafer-scale areas, driven by Mie resonance in the conical features and enhanced by the dopant-induced modification of local optical constants. Together, these works illustrate the power of biomimetic and doping strategies to produce ultrahigh broadband absorbers via straightforward processing routes.

Optical Absorption in Nanostructured Materials publication trend

The graph below shows the total number of articles in optical absorption in nanostructured materials across all publications each year (not limited to Nature Index journals).

Technical terms

Surface-plasmon resonance: Collective oscillation of conduction electrons at a metal–dielectric interface that can concentrate and absorb light.

Mie resonance: Scattering resonance of dielectric or metallic particles whose size is comparable to the wavelength of incident light, enhancing local field intensity.

Delignification: Chemical removal of lignin from wood to facilitate subsequent carbonisation and formation of hierarchical microstructures.

Metasurface: Two-dimensional array of subwavelength features designed to impose specific amplitude, phase or polarization changes on incident light.

Effective medium theory: Analytical framework treating a heterogeneous composite as a uniform material with averaged optical properties.

References

1. Wood-based superblack. Nature Communications (2023).
2. The partial space qualification of a vertically aligned carbon nanotube coating on aluminium substrates for EO applications.. Optics Express (2014).
3. Omnidirectional broadband metasurface absorber operating in visible to near-infrared regime.. Optics Express (2018).
4. Perfect blackbody sheets from nano-precision microtextured elastomers for light and thermal radiation management. Journal of Materials Chemistry C (2019).
5. Large area and broadband ultra-black absorber using microstructured aluminum doped silicon films. Scientific Reports (2017).