An infrared perfect absorber based on metal-dielectric-metal multi-layer films with nanocircle holes arrays

In this work, a metal-dielectric-metal (MDM) multi-layer perfect absorber for infrared detection technology is proposed. Its absorption and sensing properties are numerically studied by finite-different time-domain (FDTD) method. Numerical results show that the MDM structure has located surface plasmon resonance (LSPR) peak at 955 nm and the maximum absorption can obtain 99.8%. More interestingly, the absorption characteristics of the structure are independent of polarization and polarization angle, which greatly improves the convenience of the device in practical application. It also can be used as a refractive index sensor. Therefore, we believe this structure has some applications in near-infrared detection technology such as gas or liquid detection at the laboratory, plasmon absorption switches, nanosensors and other fields.