Metamaterial perfect absorber using elliptical nanoparticles in a multilayer metasurface structure with polarization independence

A metamaterial perfect absorber (MPA) using elliptical silver nanoparticles is proposed and investigated to provide 100% absorption for both transverse electric and transverse magnetic polarizations with a wide range of incident angles and polarization independence. Metamaterial absorbers with narrow absorption performance over a wide frequency range are significantly desired in sensing applications. Incident angle insensitivity and polarization angle independence are key features of MPAs. The output characteristics are examined using the three-dimensional finite difference time domain method. The effective medium theory and transmission line theory are applied to investigate the simulation results. Here, the 100% absorption occurs at resonance wavelength of λres = 2290 nm, and maximum sensitivity and figure of merit become 200 nm/RIU and 720 RIU-1, respectively. The results show that an absorption spectrum is insensitive to the incident angle of 0°-60°. The proposed device can be used as a high-performance biosensor and photodetector.