Abstract
Dielectric metasurfaces are capable of completely manipulating the phase, amplitude, and polarization of light with high spatial resolutions. The emerging design based on high-index and low-loss dielectrics has led to the realization of novel metasurfaces with high transmissions, but these devices usually operate at the limited bandwidth, and are sensitive to the incident polarization. Here, we report the realization of the polarization-independent and high-efficiency silicon metasurfaces spanning the visible wavelengths about 200 nm. The fabricated computer-generated meta-holograms exhibit a 90% diffraction efficiency, which are verified by gradient metasurfaces with measured efficiencies up to 93% at 670 nm, and exceeding 75% at the wavelengths from 600 to 800 nm for the two orthogonally polarized incidences. These dielectric metasurfaces effectively decouple the phase modulation from the polarization states and frequencies for visible light, which hold great potential for novel flat optical devices operating over a broad spectrum.
Highlights
Practical applications of plasmonic metasurfaces are, to great extent, restricted by the extremely low efficiencies caused by their intrinsically high ohmic loss and the finite scattering cross sections
Based on the Mie scattering theory, low‐loss dielectric metasurfaces can provide much stronger forth scattering by exciting both electric and magnetic resonances simultaneously22,24, which enables the effective phase manipulation for the full electric field with high transmittance[25, 29, 33]. Such a single transmission mode avoids the post‐selection of the polarization and favors the design of polarization‐independent metasurfaces 28, 29. We both theoretically and experimentally demonstrate the realization of polarization‐independent broadband dielectric metasurfaces at visible wavelengths, which would boost the practical applications of meta‐devices
The diffraction efficiency is as high as 93% in visible frequencies, demonstrating a great potential to form many novel flat optical devices such as prisms, lenses, beam generators and holograms
Summary
Practical applications of plasmonic metasurfaces are, to great extent, restricted by the extremely low efficiencies caused by their intrinsically high ohmic loss and the finite scattering cross sections. Based on the Mie scattering theory, low‐loss dielectric metasurfaces can provide much stronger forth scattering by exciting both electric and magnetic resonances simultaneously22,‐24, which enables the effective phase manipulation for the full electric field with high transmittance[25, 29, 33]. Such a single transmission mode avoids the post‐selection of the polarization and favors the design of polarization‐independent metasurfaces 28, 29. The diffraction efficiency is as high as 93% in visible frequencies, demonstrating a great potential to form many novel flat optical devices such as prisms, lenses, beam generators and holograms
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