  Recent advances in holography, wireless sensing and light fidelity
technologies have resulted in the need for antennas that can support highly
efficient beam directivity for a broad angular range. Transmitarrays have been
shown to be promising candidates for the determination of such structures.
Here, we present a comprehensive methodology for the design of subwavelength
all-dielectric flat metasurfaces with high transmission and deflection range.
The metasurfaces are CMOS compatible and can be fabricated using conventional
processing of silicon-on-insulator technology. The optimized structures exhibit
up to 95% efficiency for a wide-angle deflection range from 20{\deg} to
60{\deg} in air, at operating wavelengths near 1550 nm. Furthermore, we propose
the potential multi-wavelength and muti-mode excitation capabilities of the
designed supercell. This is achieved by shifting the resonance of each post of
the metasurface to the wavelength of interest opening up opportunities for
wavelength multiplexing with a single structure. Our results facilitate the
realization of broad angle flat deflectors and holographic devices but also
indicate that today's bulky and expensive light fidelity optical routers could
be substituted by ultra-small chips that are inexpensive to fabricate and can
be commercially implemented.
