High-Efficiency Visible Light Manipulation Using Dielectric Metasurfaces

Abstract

The development of a miniaturised device that provides efficient beam manipulation with high transmittance is extremely desirable for the broad range of applications including holography, metalens, and imaging. Recently, the potential of dielectric metasurfaces has been unleashed to efficiently manipulate the beam with full 2 pi-phase control by overlapping the electric and magnetic dipole resonances. However, in the visible range for available materials, it comes with the price of higher absorption that reduces efficiency. Here, we have considered dielectric amorphous silicon (a-Si) nanodisk and engineered them in such a way which provides minimal absorption loss in the visible range. We have experimentally demonstrated meta-deflector with high transmittance which operates in the visible wavelengths. The supercell of proposed meta-deflector consists of 15 amorphous silicon nanodisks numerically shows the transmission efficiency of 95% and deflection efficiency of 95% at operating wavelength of 715 nm. However, experimentally measured transmission and deflection efficiencies are 83% and 71%, respectively, having the experimental deflection angle of 8.40 degrees. Nevertheless, by reducing the supercell length, the deflection angle can be controlled, and the value 15.50 degrees was experimentally achieved using eight disks supercell. Our results suggest a new way to realise the highly transmittance metadevice with full 2 pi-phase control operating with the visible light which could be applicable in the imaging, metalens, holography, and display applications.