Fig. 2: Polarization-dependent local responses and omnidirectional control.
a,b, SEM images of uniformly oriented (a) and Kagome (b) metasurfaces with 800-nm resonances (overall metasurface size, 1 mm2). Scale bars, 500 nm. Insets: simulated resonant plasmonic-field enhancements for different incident linear polarization angles (black double arrows), with the calculated net current direction indicated (blue single arrows). c,d, Measured x (red) and y (blue) components of the radiated THz field (solid lines with data markers) and photocurrent (dashed lines) for the uniformly oriented (c) and Kagome (d) metasurfaces with respect to the incident linear polarization angle. Calculated linear responses (solid fills) are shown for comparison, with + and − signs indicating lobe polarity. For clarity, a small residual y component is not shown in c. e, The Kagome metasurface shows nearly constant photocurrent magnitude (purple) and continuously rotatable direction (grey), consistent with analytic predictions.
