Almost Complete Absorption of Light in Nanostructured Metallic Coatings: Blackbody Behavior

摘要

We have experimentally demonstrated blackbody-like behavior in a thin nanostructured metallic layer shaped in the form of a composite deep diffraction grating. This behavior is recorded over a wide optical wavelength range (240-550 nm) and for a broad range of angles of light incidence (0-75°) for samples with metal thickness of just 90 nm. The strong absorption at a level of 97-99% is observed for one light polarization and is attributed to excitation of localized plasmons coupled to incident light waves. An effective-medium approach provides a satisfactory qualitative description of the reflection and transmission spectra in our samples and confirms their blackbody behavior.