Fig. 2: Nanophotonic design of the hybrid-2D metasurface.
From: Electrically tunable strong coupling in a hybrid-2D excitonic metasurface for optical modulation
a Standing wave profile of the electric field under normal-incidence transverse magnetic (TM)-polarized illumination showing minimal field overlap with the monolayer (blue line at z = 0 μm). b Modeled real (n, solid) and imaginary (k, dashed) components of the complex refractive index of monolayer WS2 at intrinsic (blue) and strong n-type (red) doping. c Numerically simulated angular dispersion of the designed modulator under TE-polarized illumination with monolayer WS2 at strong n-type doping and d intrinsic doping. In the latter case, the A-exciton is strongly coupled to the GMR, resulting in the formation of a 38.2 meV gap (indicated) at the exciton energy. e Grating period dependence of the reflectance at intrinsic doping and strong n-type doping (inset). The calculated upper (UP) and lower polariton (LP) branches of the coupled mode analysis are represented by the white dashed lines. In the inset, the A-exciton wavelength λA is represented by the dashed line (black) and the GMR dispersion by the dotted line (white). f Modulation depth as function of grating period, with the designed period Λ indicated (dashed line). The color scale is capped at ±12 dB for visibility
