Optical nanoantennas are widely used to build absorbing metasurfaces with applications in photodetection, solar cells, and sensing. Most of the time, the nanoantennas are assembled as a periodic distribution, but there have been various works where disordered arrays are used, either to get rid of diffraction orders or due to a fabrication process that prevents any determined distribution. Here, we investigate both theoretically and experimentally the unavoidable scattering introduced by such disorders. By introducing a perturbation on the positions of 1D arrays of metal-insulator-metal (MIM) nanoantennas, the light is scattered rather than increasingly absorbed. The scattering occurs only in the plane of incidence and on a given spectral range. We show how this scattering can be manipulated from 0% to 55% of the incoming light.
Sub-wavelength metallic grooves behave as Fabry-Perot nanocavities able to resonantly enhance the absorption of light as well as the intensity of the electromagnetic field. Here, with a one-mode analytical model, we investigate the effect of a correlated disorder on 1D groove arrays i.e., randomly shaped and positioned grooves on a metallic layer. We show that a jitter-based disorder leads to a redistribution of energy compared to the periodic case. In an extreme case, a periodic diffracting array can be converted into a highly scattering array (98% at λ = 2.8 µm with a 1 µm full width at half maximum). Eventually, we show that the optical response of combinations of variously shaped grooves can be well described by the individual subset behaviors.
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