Wideband omnidirectional infrared absorber with a patchwork of plasmonic nanoantennas

In this Letter, we demonstrate experimentally that a patchwork of four metal-insulator-metal patches leads to an unpolarized wideband omnidirectional infrared absorption. Our structure absorbs 70% of the incident light on a 2.5 mu m bandwidth at 8.5 mu m. It paves the way to the design of wideband efficient plasmonic absorbers in the infrared spectrum. (C) 2012 Optical Society of America