Tunable perfect absorber based on gold grating including phase-changing material in visible range

Metamaterial-based perfect absorber has attracted wide attention for its many applications. Here, we present a theoretical study of tunable plasmonic absorption based on a gold grating nanostructure with phase-changing material. The structure consists of a metal layer covered with metal grating for perfect optical absorption. To make the optical absorption tunable, we design a Ge2Sb2Te2 (GST) layer located between the metal layer and the metal grating. Our design of the metamaterial structure can realize tunable perfect absorber through crystalline and amorphous phase transitions in near visible range. The effect of geometrical parameters on absorption is also studied. The field distribution is presented to illustrate the absorption mechanism. The results will pave the way towards the dynamical optical absorption control in many applications, including plasmonic switch, plasmonic modulator and photodetectors.