Abstract

Recently, the concept of the geometric Pancharatnam-Berry (P-B) phase has been successfully extended to optical metasurfaces operating in the nonlinear regime^1–3. It was shown that the nonlinear geometric P-B phase of each meta-atom is determined by the spin of the fundamental wave, the spin of the nonlinear signal, and the order of the nonlinear process¹. By manipulating the interferences of SHG waves from two meta-atoms within one unit-cell, we demonstrate a grey-scale image encryption in the nonlinear signal. We successfully demonstrate spatially variant SHG for real space image generation directly from the metasurface interface by controlling the phase difference of the nonlinear polarization between neighboring meta-atoms.

© 2017 IEEE