Generation of spin-multiplexing focusing based on polarization-tuned all-dielectric metasurface

It is essential to develop a device with miniature, high-resolution and low-cost features for simultaneously achieving controllable bright-field imaging and spiral phase contrast imaging to detect and recognize of an object. Benefiting from the exotic ability of the metasurface in arbitrarily manipulating wavefront at the subwavelength scale, here, we propose and demonstrate a single-layer polarization-tuned all-dielectric metasurface based on Pancharatnam-Berry phase enabling spin-multiplexing focusing in the visible light. Under the incidence of the linearly polarized wave, it can generate two different spin-dependent focal points that a focus carries vortex phase and other focus carries hyperbolic phase in both transverse and longitudinal directions, which means that bright-field imaging and spiral phase contrast imaging can be simultaneously achieved for distinguishing precisely the overall morphologies and edges of an object. Consequently, the proposed approach is straightforward and also provides a theory to develop other multifunctional meta-devices for diverse optical wave manipulations in anticounterfeiting, high-density information encryption, holography, and display.