Fano-resonance of reshaping infrared cross-shape metamaterial (CSM)

An infrared (IR) cross-shape metamaterial (CSM) is presented. The configuration is composed of double Au layers with cross-shape nanostructures. The aspect ratio and length ratio of CSM are compared and discussed to investigate the Fano-resonance within CSM nanostructures. The electromagnetic responses exhibit large tuning range, tunable broad and narrow bandwidths characteristics. By tailoring the aspect ratio of CSM, the resonance could be modified with bidirectional tuning in a range of 650 nm. While the change of length ratio of CSM, there are narrowband resonances around 4.6 $\mu \text{m}$ and broadband resonances in the range of 5.0 to 6.5 $\mu \text{m}$. These characteristics of CSM with different aspect ratio and length ratio could be potentially used in IR narrowband and broadband filter. To further increase the flexibility of CSM, we propose a tunable CSM using MEMS-based electrothermal actuation mechanism to perform actively tunable narrowband and broadband filter. This study provides a unique approach to realize an IR filter with high-flexibility.