Taming the Electromagnetic Boundaries via Metasurfaces: From Theory and Fabrication to Functional Devices

Figure 14

(a) A schematic of the THz measurement with THz wave normal incident from the left side of Si substrate and square mesh AR coating on the right side of Si substrate. (b) THz TDS transmission signals under normal incidence. The solid curve is for bare Si and the dashed and dotted curves are for AR-coated Si in horizontal polarization and vertical polarization, respectively. (c) FFT of the THz TDS spectra. (d) Schematic of the metasurface antireflection coating on a germanium substrate, consisting of a periodic array of gold cross-resonators on top of a dielectric layer. (e) Schematic of multireflection within the metasurface antireflection structure. (f) The SEM image of a fabricated metasurface antireflection structure. (g) Calculated optical reflectance () and transmittance () using full-wave numerical simulation. Figures are reproduced from (a)–(c) [41] and (d)–(g) [96].

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