A Spin‐Encoded All‐Dielectric Metahologram for Visible Light

Abstract

Dielectric materials that are low‐loss in the visible spectrum provide a promising platform to realize the pragmatic features of metasurfaces. Here, all‐dielectric, highly efficient, spin‐encoded transmission‐type metaholograms (in the visible domain) are demonstrated by utilizing hydrogenated amorphous silicon (a‐Si:H). In comparison to previously reported visible metaholograms based on TiO2 and other dielectric materials, all‐dielectric metasurfaces provide a cost‐effective more straightforwardly fabricated (aspect ratio 4.7), CMOS compatible, and comparably efficient solution in the visible domain. A unique way of utilizing polarization as an extra degree of freedom in the design to implement transmission‐type helicity‐encoded metaholograms is also proposed. The produced images exhibit high fidelity under both right and left circularly polarized illuminations. The proposed cost‐effective and CMOS‐compatible material and methods open up an avenue for on‐chip development of numerous new phenomena with high efficiency in the visible domain.

Scalable and High-Throughput Top-Down Manufacturing of Optical Metasurfaces

“…In addition to color filters, holography is another coloration application of metasurfaces. In metaholograms, each meta-atom on the metasurface is designed to resonate the incident light at a certain visible frequency, so the desired image can be displayed [ 14 , 15 , 16 , 17 , 18 , 19 , 20 ]. K. Kim and G. Yoon have also shown that metaholograms can be realized at a large scale using nanoimprint lithography (NIL) [ 16 ].…”

Metasurfaces: Subwavelength nanostructure arrays for ultrathin flat optics and photonics

“…18 In addition, in optical devices based on dielectric metasurfaces, the refractive index n of the dielectric is not large, so a nanostructure with high aspect ratio (AR) is often required. For example, titanium dioxide (TiO 2 ) or gallium nitride (GaN) require a high AR of 10 to 15, and amorphous silicon requires an AR of 4.7; 19 such high values complicate nanofabrication and thus limit further device miniaturization. A Mie resonator has been implemented by stacking atomically thin transition-metal dichalcogenide (TMDC) materials.…”

Recent Advances in Non-Traditional Elastic Wave Manipulation by Macroscopic Artificial Structures

“…The physical mechanism of the MSs exploits adjustment of wave phase shifts, unlike bulk MTMs, in which waves are manipulated by changing the effective parameters of the material. MSs can be used in applications such as anomalous reflection and refraction [132,133], polarization conversion [134,135], focal lenses [136][137][138] and holograms [139][140][141][142]. MSs are based on the generalized Snell's law with phase discontinuity [143].…”