Figure 3
From: Directly patterned substrate-free plasmonic “nanograter” structures with unusual Fano resonances
Fano resonances from vertical U-shaped SRRs standing along horizontal rectangular hole arrays in a free-standing metallic film (MH-VSRRs). (a) Schematic of the MH-VSRR structure. (b, c), SEM images of the fabricated MH-VSRRs, with h = 1.2 µm, l = 1.0 µm, w = 340 nm, ax = ay = 2.0 µm and px = py = 3.0 µm. (d, e), As-measured transmission spectra of the MH-VSRRs shown in c under normal incidence with the electric field polarized along the x- and y-direction, respectively. Normal incidence is employed throughout this work. The gray spectral region at approximately 4.2 µm is a high-absorption region from CO2 in the FTIR chamber and was omitted for clear comparison with simulations. (f, g), Simulated transmission spectra of the MH-VSRRs corresponding to d and e, respectively. The corresponding spectra of rectangular hole arrays in metallic films (MHs) in the absence of VSRRs are also plotted for comparison in Figure 3d–3g. FTIR, Fourier transform infrared spectroscopy.
