  Metasurfaces possess the outstanding ability to tailor phase, amplitude and
even spectral responses of light with an unprecedented ultrahigh resolution,
thus have attracted significant interests. Here, we propose and experimentally
demonstrate a novel meta-device that integrates color printing and
computer-generated holograms within a single-layer dielectric metasurface by
modulating spectral and spatial responses at subwavelength scale,
simultaneously. In our design, such metasurface appears as a microscopic color
image under white light illumination, while encrypting two different
holographic images that can be projected at the far-field when illuminated with
red and green laser beams. We choose amorphous silicon dimers and nanofins as
building components and use a modified parallel Gerchberg-Saxton algorithm to
obtain multiple sub-holograms with arbitrary spatial shapes for image-indexed
arrangements. Such a method can further extend the design freedom of
metasurfaces. By exploiting spectral and spatial control at the level of
individual pixels, multiple sets of independent information can be introduced
into a single-layer device, the additional complexity and enlarged information
capacity are promising for novel applications such as information security and
anti-counterfeiting.
