Ultra-Narrowband Anisotropic Perfect Absorber Based on α-MoO3 Metamaterials in the Visible Light Region

Abstract

Optically anisotropic materials show important advantages in constructing polarization-dependent optical devices. Very recently, a new type of two-dimensional van der Waals (vdW) material, known as α-phase molybdenum trioxide (α-MoO3), has sparked considerable interest owing to its highly anisotropic characteristics. In this work, we theoretically present an anisotropic metamaterial absorber composed of α-MoO3 rings and dielectric layer stacking on a metallic mirror. The designed absorber can exhibit ultra-narrowband perfect absorption for polarizations along [100] and [001] crystalline directions in the visible light region. Plus, the influences of some geometric parameters on the optical absorption spectra are discussed. Meanwhile, the proposed ultra-narrowband anisotropic perfect absorber has an excellent angular tolerance for the case of oblique incidence. Interestingly, the single-band perfect absorption in our proposed metamaterials can be arbitrarily extended to multi-band perfect absorption by adjusting the thickness of dielectric layer. The physical mechanism can be explained by the interference theory in Fabry–Pérot cavity, which is consistent with the numerical simulation. Our research results have some potential applications in designs of anisotropic optical devices with tunable spectrum and selective polarization in the visible light region.

Polarization Independent Metamaterial Absorber with Anti-Reflection Coating Nanoarchitectonics for Visible and Infrared Window Applications

“…The blocking capability of EM waves can be understood by skin depth , where wavelength is proportional to skin depth. So, a higher skin depth is required to block the larger wavelength [ 17 , 51 ]. Figure 7 shows the investigation of absorption property for different back layer thicknesses from h1 = 105 to 65, where the absorption is reduced in the near-infrared region with the decrease of the thickness h1.…”

Structures, principles, and properties of metamaterial perfect absorbers

“…This can be explained by the interference theory of Fabry–Perot cavity resonance, which states that the process of increasing the thickness of the silica layer from 1.185 to 1.215 is a deviation from the optimal thickness. Jin et al 42 utilized the anisotropy of a novel two-dimensional van der Waals (vdW) material to achieve ultra-narrowband perfect absorption and single band to multi-band absorption by adjusting the thickness of the intermediate dielectric layer. The structural diagram is shown in Fig.…”

Multi-band perfect absorber based on an elliptical cavity coupled with an elliptical metal nanorod

“…[14][15][16][17] For example, Jin et al proposed an ultra-narrow single-band absorber using a-MoO 3 material. 18 Tao et al designed a dual-band absorber at terahertz frequencies. 19 Shen et al proposed a triple-band absorber based on a nested gold square-ring structure.…”