Fig. 2
Analysis of the reflectance for the (1,3) metasurface device when the metal electrode voltage is − 0.9 V. (a) From the reflectance data, we extract the local maximum reflectance (red), local minimum reflectance (green), and absorption (calculated as the difference between the local maximum and minimum reflectance, shown in blue) when the antenna voltage is 1.3 V. The numbers at the peaks correspond to the Fabry-Perot resonance mode number, \(k_0 + k\). (b) A contour plot of the extracted absorption is shown for different antenna voltages. The cyan-colored region is the area of no interest, as the reflectance in this region is higher than that of the highest contour line. (c) From the reflectance, the experimental peak wavelength (shown in black) is collected and fitted (in red) using the perturbed Fabry-Perot resonance equation (Eq. 3). By analyzing the difference between the experimental data and the fitting, we can extract the phase information of the metasurface (in magenta) using equation (Eq. 2). By focusing on the phase change from positive to negative, we can obtain the resonance wavelength. (d) The obtained resonance wavelength with different voltages of the antenna electrode and the metal electrode in the (1, 3) metasurface device.
