Fig. 1: Nonlinear radiation with arbitrary chirality generated by a resonant metasurface.
From: Nonlinear chiral light generation from resonant metasurfaces
A Schematics for the generation of LCP (left panel) and RCP (right panel) THG with the same Si metasurface. The reversal of THG handedness is achieved with a simple change in polarization direction (θ). The insert shows the three-dimensional schematic diagram of one unit cell with structural parameters. B Linear transmission under the y-linearly polarized input (solid line) and the corresponding CD (dashed line) of the Si metasurface. C shows the numerically calculated LCP (solid line) and RCP (dashed line) THG spectra with different polarization angles of θ = 83.5° and 96.5°, respectively. The resonant wavelength is marked by a vertical dash-dotted line. The “a.u.” represents “arbitrary units”. D The winding path of numerically calculated THG chirality (solid line) on the surface of Poincare sphere as a function of polarization angle of fundamental waves. The dots represent the fitting results with the theoretical model. Here the size parameters are a = 434 nm, w1 = 379 nm, w2 = 89 nm, l = 160 nm, and h = 234 nm.
