Figure 1

(Color online) (a) The detail structure of the double-layered and orthogonally rotated USR pair with $\mathit{a}=4.0\mu \text{m}$, $\mathit{b}=1.0\mu \text{m}$, and $\mathit{g}=0.6\mu \text{m}$. The thickness of each U pattern is 100 nm. (b) The calculated transmission coefficient of USRs for normal incidence, and resonance occurs at ${\omega }_L$ and ${\omega }_H$. In the calculation the ambient is set as vacuum, and the polarization is along $45°$. (c) and (d) The surface electric current density excited on USRs at lower $\left({\omega }_L\right)$ and higher $\left({\omega }_H\right)$ resonant frequencies. The small arrows represent the surface current distribution. By setting $\mathit{x}$ and $\mathit{y}$ axes along the diagonal directions of USRs, the surface current can be projected along $\mathit{x}$ and $\mathit{y}$ directions, respectively.Reuse & Permissions

Figure 2

(Color online) (a) The unit cell constructed by four pairs of USRs. The unit is arranged in a simple square lattice and the lattice parameter is $12\mu \text{m}$. (b) The amplitudes of $t_{\parallel }$, $t_{\perp }$, $r_{\parallel }$, and $r_{\perp }$. (c) The amplitudes of $t_L$, $t_R$, and $r$. (d) The diagram to show the phase difference $\delta$ between $t_{\perp }$ and $t_{\parallel }$ as a function of wave number, and the azimuth angle of the principal axis of polarization of transmission wave $\theta$ as a function of wave number.Reuse & Permissions

Figure 3

(Color online) The retrieved effective optical parameters of USR arrays. (a) and (b) illustrate the real and imaginary parts of the refractive index for LCP and RCP light, respectively. The shadow denotes the occurrence of negative refractive index. (c)–(f) illustrate the real and imaginary parts of the permittivity $ϵ$, permeability $\mu$, chiral parameter $\xi$, and the impedance $Z$.Reuse & Permissions

Figure 4

(Color online) (a) The scanning electron micrograph of the double-layered USR arrays. The double-layer structure can be easily identified from the inset. (b) The schematics of the measurement setup. In the measurement, the arms of USRs are set in parallel with $\mathit{X}$ and $\mathit{Y}$ directions. The polarizer in front of and after the sample can be independently rotated with angle ${\theta }_1$ and ${\theta }_2$, respectively. (c) Experimentally measured transmission spectra with different polarizations of ${\theta }_1$ and ${\theta }_2$. The red (light gray) solid line: ${\theta }_1={\theta }_1=-45°$; the blue (dark gray) solid line: ${\theta }_1={\theta }_1=0°$; the black solid line: ${\theta }_1={\theta }_1=45°$; the red (light gray) dash dot line: ${\theta }_1=-45°$ and ${\theta }_2=45°$; the black dash line: ${\theta }_1=45°$ and ${\theta }_2=-45°$; the blue (dark gray) dot line: ${\theta }_1=90°$ and ${\theta }_1=0°$. (d) Simulation of the transmission $T_{\parallel }$ and $T_{\perp }$. In simulation damping constant used in Drude model is doubled to fit the loss in real system.Reuse & Permissions