Reconstruction of multidimensional nonlinear polarization response of Pancharatnam-Berry metasurfaces

International audienceThe Pancharatnam-Berry (PB) metasurfaces have been considered as the innovative optical devices for efficient manipulation of both the phase and the polarization of electromagnetic field. Here, we present the simultaneous generation of circularly-, elliptically-, and linearly-polarized states from a single linearly-polarized incident beam by revealing the mechanism of polarization modulation of the nonlinear PB metasurface. We further demonstrate the quantitative description for the detected signal of each scattering channel containing different constructive and destructive interferences of nonlinear response components. This novel mechanism provides a new strategy to realize the metasurface-based polarization control for the reconstruction of different contributions of nonlinear response. As an illustration, by optimizing polarization configurations of the incident light beams, the third-order nonlinear response of the phase gradient unit cell is reconstructed from the multi-channel scattering waves. Using the tools of multidimensional spectroscopy, we demonstrate the possibility to track both stationary and transient delocalized charge distributions via detecting plasmonic populations and coherences. These theoretical results provide a solid platform for the new generation of characterization instruments based on the metasurfaces