Broadband polarization-insensitive Jerusalem-shaped metasurface absorber based on phase-change material for the visible region

Abstract

In this paper, a broadband metasurface absorber using phase change material covering the visible region (500 THz to 740 THz) is numerically investigated. The top metallic layer comprises an array of Jerusalem shaped structures periodic in the x-y direction placed above the Ge2Sb2Te5 (GST) layer. The GST layer is followed by a thick metallic layer and silicon dioxide (SiO2). The intermediate dielectric layer in between two metallic layers is made of phase change material. The tri-layer structure is placed above the SiO2 with average absorption is achieved with an efficiency of 92.86% using the amorphous GST (a-GST) phase in the dielectric layer. The average absorption of a-GST is more in the crystalline GST (c-GST) phase in the proposed absorber. The change in the absorption peaks are observed using GST material in the terahertz region. The proposed broadband Jerusalem-shaped metasurface absorber is polarization insensitive due to its symmetrical structure.