We present two Fano-type resonances from a single set of paired split-ring resonators (SRRs) with broken structural symmetry in the mid-infrared regions. These paired SRR metamaterials are designed by the planar integration of two geometry-different SRRs, referred to as inner SRRs and outer SRRs, where the interplay of these two SRR elements constitute two Fano-type resonances at 7.4 μm and 2.8 μm, respectively. Investigations of their sensing characteristics are carried out systematically, indicating that these SRR-based sensors can be realized using the shift of resonance wavelength in response to the refractive-index (RI) change with remarkable sensitivity. Furthermore, evolution of the sensing performances is performed by separately investigating the spatial positions of the RI sensors, where the position-dependent sensing characteristics are numerically evidenced. It is found that the most active region for possessing RI sensing is located inside the inner SRR components in these coupled SRR-based sensors. In-depth studies of these dual-band coupled resonances are anticipated to benefit the development of RI sensing designs.
All Science Journal Classification (ASJC) codes
- Electronic, Optical and Magnetic Materials
- Condensed Matter Physics
- Acoustics and Ultrasonics
- Surfaces, Coatings and Films