Polarization-independent and high-efficiency dielectric metasurfaces for visible light

Abstract

Artificial 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, for the first time we report experimentally the polarization-independent and highefficiency dielectric metasurfaces spanning the visible wavelengths about 200 nm, which are of importance for novel flat optical devices operating over a broad spectrum. The diffraction efficiencies of the gradient metasurfaces consisting of the multi-fold symmetric nano-crystalline silicon nanopillars are up to 93% at 670 nm, and exceed 75% at the wavelengths from 600 to 800 nm for the two orthogonally polarized incidences. These dielectric metasurfaces hold great potential to replace prisms, lenses and other conventional optical elements.

Metasurface holography: from fundamentals to applications

“…Furthermore, it was reported that meta-atoms designed based on Huygens' principle with a multi-fold rotational symmetry had a polarization-independent response. The distortion induced by the mismatched lattices was also found to be very weak [65].…”

Chirality‐Assisted High‐Efficiency Metasurfaces with Independent Control of Phase, Amplitude, and Polarization

“…The explosive field of metasurface has intrigued a huge interest from both physics and engineering communities due to its exotic behaviors and promising applications. It, composed of a mass of subwavelength‐spaced meta‐atoms, has afforded extraordinary capabilities to manipulate electromagnetic (EM) waves . The local amplitude, phase, and polarization are three important characteristics for output EM wavefront control, and previous pursuing of light manipulation via metasurfaces could be generally subjected into processing one or two of them.…”

“…On the other hand, much attention has been paid to enhance the efficiency which is critically important for photonic devices. To date, different approaches were proposed to circumvent it in both reflection and transmission geometries, for example, by using active phase compensation, satisfying certain phase criterion, incorporating both electric and magnetic responses, low‐loss all‐dielectric metasurfaces, etc. However, these designs are confined to phase‐ or polarization‐only modulation, making the kaleidoscopic wavefront control particularly challenging.…”

Highly efficient holograms based on c-Si metasurfaces in the visible range

“…For instance, a [0-2π] phase control has been achieved with tall cylinders (nanoposts) with high transmission [19][20][21][22]. In fact, the high diffraction efficiency provided by dielectric metasurfaces has been explored in many other classical applications, such as lenses [23][24][25], holograms [17][18][19]22,[26][27][28][29][30], wave plates [31], anomalous refraction generation [20,32], and vortex beam generation [32,33].…”

“…The choice of materials, as expected, plays an important role in the structures design. High index materials such as titanium dioxide (TiO 2 ) [25,29,34,35], silicon nitride (Si 3 N 4 ) [21], and silicon [17][18][19][20][26][27][28][30][31][32]36] are usually the preferred choice for this task. Silicon is particularly interesting for metasurface applications not only for its compatibility with CMOS processes, but also for its high refractive index that allows high-contrast gratings to be fabricated with low aspect ratio.…”