Large-area, wide-angle, spectrally selective plasmonic absorber

Nanohmics, Inc. 6201 E. Oltorf, Suite 400, Austin, TX 78741(Dated: April 18, 2011)A simple metamaterial-based wide-angle plasmonic absorber is introduced, fabricated, and exper-imentally characterized using angle-resolved infrared spectroscopy. The metamaterials are preparedby nano-imprint lithography, an attractive low-cost technology for making large-area samples. Thematching of the metamaterial’s impedance to that of vacuum is responsible for the observed spec-trally selective “perfect” absorption of infrared light. The impedance is theoretically calculatedin the single-resonance approximation, and the responsible resonance is identified as a short-rangesurface plasmon. The spectral position of the absorption peak (which is as high as 95%) is exper-imentally shown to be controlled by the metamaterial’s dimensions. The persistence of “perfect”absorption with variable metamaterial parameters is theoretically explained. The wide-angle natureof the absorber can be utilized for sub-diffraction-scale infrared pixels exhibiting spectrally selectiveabsorption/emissivity.I. INTRODUCTION