High‐transmission dielectric metasurface with 2π phase control at visible wavelengths

Abstract

Recently, metasurfaces have received increasing attention due to their ability to locally manipulate the amplitude, phase and polarization of light with high spatial resolution. Transmissive metasurfaces based on high-index dielectric materials are particularly interesting due to the low intrinsic losses and compatibility with standard industrial processes. Here, it is demonstrated numerically and experimentally that a uniform array of silicon nanodisks can exhibit close-to-unity transmission at resonance in the visible spectrum. A single-layer gradient metasurface utilizing this concept is shown to achieve around 45% transmission into the desired order. These values represent an improvement over existing state-of-the-art, and are the result of simultaneous excitation and mutual interference of magnetic and electric-dipole resonances in the nanodisks, which enables directional forward scattering with a broad bandwidth. Due to CMOS compatibility and the relative ease of fabrication, this approach is promising for creation of novel flat optical devices.

Multiwavelength polarization-insensitive lenses based on dielectric metasurfaces with meta-molecules

“…From the multiple designs proposed so far, dielectric transmitarrays [6][7][8][9][10][11][12][13][14][15] are some of the most versatile metasurfaces because they provide high transmission and subwavelength spatial control of both polarization and phase. Several diffractive optical elements, including high-NA lenses and simultaneous phase and polarization controllers have recently been demonstrated with high efficiencies [10,11].…”

Low Contrast Dielectric Metasurface Optics

“…Thus far, high quality metasurface optical elements based on metals 5,17 , titanium oxide 18,19 , and amorphous silicon 20,21 have been demonstrated. Unfortunately, metals are significantly lossy at optical frequencies 22 , titanium oxide lacks CMOS compatibility, and amorphous silicon absorbs light in the visible and near-infrared spectrum (~400-900nm).…”

Rapid Design of Wide-Area Heterogeneous Electromagnetic Metasurfaces Beyond the Unit-Cell Approximation

“…The unit cell approximation has several limitations; chiefly, it tends to be inadequate in the presence of strong phase gradients, interactions between neighboring pillars, and oblique incidence angles. These constraints become important for instance in the case of a focusing lens [14,15,17,19].…”

“…This technique is similar to the Extended Local Periodicity (ELP) approach [18] proposed for reflectarray design. Specifically, we focus our attention to a beam deflector element which is a commonly used structure for benchmarking metasurfaces design strategies [17,19,20] as the transmission efficiencies can be compared across designs. The beam deflector element changes the direction of an normally incident plane wave by giving it a predesigned inclination with respect to the normal.…”