Fig. 1. (a) Design of folding metamaterial. The folding metamaterial comprises SRRs with nano-profiles. (b) Geometrical dimensions of folding and common metamaterials. (c) Illustration of biosensor based on folding metamaterial.

Fig. 2. Scanning electron microscope images of folding metamaterial with height of 20.7 μm at (a) 45° and (b) 80° angles of incidence. Scanning electron microscope images of common metamaterial with height of 500 nm at (c) 45° and (d) 80° angles of incidence.

Fig. 3. (a) Experimental (solid lines) and simulated (dashed lines) spectra of folding and common metamaterials. (b) Surface current distributions of SRRs with and without nano-profiles. (c) Theoretical models of SRRs with and without nano-profiles.

Fig. 4. (a) Near-field distributions of SRRs with and without nano-profiles. (b) Experimental spectra of fluidic cells with folding metamaterials at various heights (h) of SRRs.

Fig. 5. (a) Experimental spectra of fluidic sample with folding metamaterial imbedded into air and rabbit-blood layers. The green curve is the terahertz spectrum of the rabbit-blood sample without a metamaterial. (b) Experimental spectra of fluidic sample with common metamaterial imbedded into air and rabbit-blood layers.

Fig. 6. Fabrication of (a) folding and (b) common metamaterials.

Fig. 7. Simulated spectra of the folding and solid metamaterials with a thickness of 20.7 μm. The insets present the simulated models and surface current distributions of folding and solid metamaterials.