Wideband long wave infrared metamaterial absorbers based on silicon nitride

Abstract

In this paper, we present silicon nitride metamaterial absorber designs that accomplish large bandwidth and high absorption in the long wave infrared (LWIR) region. These designs are based on the metal-insulator-metal topology, insulator (silicon nitride), and the top metal (aluminum) layers are optimized to obtain high absorptance values in large bandwidths, for three different silicon nitride based absorber structures. The absorption spectrum of the final design reaches absorptance values above 90% in the wavelength interval between 8.07 μm and 11.97 μm, and above 80% in the wavelength interval between 7.9 μm and 14 μm, in the case of normal incidence. The difficulty in the design process of such absorbers stems from the highly dispersive behavior of silicon nitride in the LWIR region. On the other hand, silicon nitride is a widely used material in microbolometers, and accomplishing wide band absorption in silicon nitride is crucial in this regard. Therefore, this study will pave the way for more efficient infrared imaging devices, which are crucial for defense and security systems. Additionally, such designs may also find applications in thermal emitters.

CMOS-compatible mid-IR metamaterial absorbers for out-of-band suppression in optical MEMS

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An Infrared Metamaterial Broadband Absorber Based on a Simple Titanium Disk with High Absorption and a Tunable Spectral Absorption Band

“…[5][6][7][8][9][10] The first microwave metamaterial absorbers were demonstrated experimentally by Landy et al, [11] since when there have been many reports describing terahertz, infrared, and visible metamaterial absorbers. [12][13][14][15] Metamaterial absorbers function via the principle that plasmon resonances produced by light incident on a metal surface significantly enhance the electromagnetic field around the metal medium. [16] Plasmon resonance is a coupled surface electromagnetic mode formed by free electrons on a metal surface interacting with photons under the excitation of a light field.…”

Ultra-High Refractive Index Sensing Structure Based on a Metal-Insulator-Metal Waveguide-Coupled T-Shape Cavity with Metal Nanorod Defects

“…Mid-infrared (MIR) spectrum is in the wavelength range of 2 μm to 20 μm, which represents the molecular fingerprint zone [25], and the potential MIR applications have been widely reported in many works [26,27,28,29,30,31]. In particular, one of the purposes of plasmonic MIM waveguide sensors is necessary for atmospheric transparent window of MIR spectrum from 2 μm to 12 μm [32]. Although there have been reported a number of articles regarding diverse plasmonic MIM waveguides, the interaction nature of incident MIR EM wave and tunable MIM waveguide are investigated less.…”