All-dielectric single-layered achiral structures for simultaneous conversion circular dichroism and wavefront engineering for visible light

The simultaneous conversion circular dichroism and wavefront shaping play a vital role in light-matter interactions. The conversion circular dichroism achieved either by intrinsic chirality of nano-antennas or by using multilayer structures which have fabrication complexities. We propose a unique single-layered all-dielectric metasurface for circular asymmetric transmission in the visible regime. We introduce the combination of achiral structures as the building block of metasurface for the simultaneous conversion circular dichroism and wavefront modulation by utilizing hydrogenated amorphous silicon (a-Si:H). The proposed material is a low-loss and a CMOS compatible solution for realizing efficient all-dielectric metasurfaces for the visible domain. The demonstrated methodology exhibits highly efficient transmittance under right circularly polarized (RCP) illumination while completely blocking the light for the opposite spin of the incident light. The multifunctionality of the proposed metasurface can provide a promising route for chiral imaging, CD spectroscopy and spin-selective optical systems