Wideband omnidirectional infrared absorber with a patchwork of plasmonic nanoantennas

Abstract

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 μm bandwidth at 8.5 μm. It paves the way to the design of wideband efficient plasmonic absorbers in the infrared spectrum.

Perfect Light Absorbers Made of Tungsten-Ceramic Membranes

“…We show that the W-SiN membranes are able to serve as PLAs even when they have subwavelength thickness, suggesting that they can function as low-power-consumption thermal emitters near the visible range. We also clarify that the working mechanism of the PLAs is unconventional, robust, and different from that of noble-metal-insulator systems studied so far [2][3][4][5][6].…”

“…To make the application clear, we design perfect light absorbers (PLAs) suitable for thermal emitters in the short-wavelength infrared range of 1-2 µm. Thermal emitters made of nanostructured materials are currently optimized for the mid-infrared range of 2-5 µm, using metal-insulator-metal structures that typically comprise noble metals [2][3][4][5], aluminum [6], etc., as constituent materials; however, these metals cannot withstand high temperatures.…”

“…However, it has been difficult to attain PLAs over the whole wavelength range. Accordingly, PLAs based on the artificially designed structures were conceived for the particular wavelength ranges [2][3][4][5][6]; in fact, the PLAs do not look like black bodies. Thus, there are distinct differences between black-body-based and artificial-structure-based PLAs.…”

“…Note that Equation (1) is represented in the (0, 1) range where 0 and 1 denote 0% and 100%, respectively. Perfect light absorption is related to perfect emittance by reciprocity [10]; therefore, when thermal emitters were produced, researchers tried to attain perfect-absorption structures [2][3][4][5][6]. Recently, nearly perfect absorption was observed in stacked complementary structures [11], which show significant enhancement of electric-dipole emission loaded on the outmost surfaces [12][13][14].…”

Broadband Millimeterwave Metamaterial Absorber Based on Embedding of Dual Resonators

“…Broadband absorber at IR wavelength designed using multiplexed metal patches has been shown to achieve 98% absorption over 3.4-3.55 µm [19]. Broadband IR absorber is also realized using plasmonic nanoantennas with multiple resonance [20] and dual resonance [21] absorption responses.…”