Total light absorption in a wide range of incidence by nanostructured metal without plasmons

Abstract

International audienceMetals structured by nanocavities have recently been demonstrated to efficiently absorb light in a wide range of angle of incidence. It has been assumed that nanovoid plasmons are at the origin of the strong absorption. It is shown in this paper that it is possible to totally absorb incident light without plasmons. To avoid their excitation, a diffraction grating consisting of cylindrical cavities in a metallic substrate is illuminated in transverse electric (TE) polarization. It is found that cylindrical cavities can sustain cavity resonances with a high enhancement of the light intensity, provoking a total absorption of light in a wide range of incidence