Rotationally tunable polarization-insensitive single and multifocal metasurface

Abstract

Metasurfaces with superior capabilities to tailor wave fronts of light have become one of the most widely investigated optical elements. Incorporating tunable features into the metasurface design is required. In this study, we have proposed and designed highly efficient rotationally tunable metasurface lens structures inspired by Moiré lenses operating at a 532 nm wavelength. The proposed structures consist of two cascaded all-dielectric metasurfaces, which have reverse phase profiles with respect to each other. The metasurfaces are designed with periodically arranged TiO2 nano-rods on a SiO2 substrate in a square lattice. We demonstrated that the focal length changes nonlinearly according to the mutual rotation of metasurfaces from 30° to 150° with a focusing efficiency as high as 55% and a wide focal length variation between 11.4 μm and 4.2 μm. Moreover, we have designed and proposed a tunable polarization-insensitive multifunctional focal system. Using the proposed multifunctional focal system, focal planes can be formed in consecutive planes and the number of focal planes can be made single or multiple.

Tunable metasurfaces towards versatile metalenses and metaholograms: a review

“…Furthermore, rotation of a metalenses doublet can tune its focal length. [107][108][109][110] Mutual rotation of doublet metalenses has been shown to tune the focal length using Moiré metalenses that are axially asymmetric doublet lens 97 [Fig. 3(c)].…”

Principles, Functions, and Applications of Optical Meta‐Lens

“…[ 151 ] proposed a rotationally tunable polarization‐dependent varifocal metasurface, and Yilmaz et al. [ 152 ] demonstrated a polarization‐independent varifocal metasurface. Subsequently, Guo et al.…”

“…[ 147,148 ] A derivative of the Alvarez system is also presented where the two lenses are coaxially rotated rather than being parallelly moved, which is inspired by the Moiré lens. [ 149–153 ] Cui et al. [ 151 ] proposed a rotationally tunable polarization‐dependent varifocal metasurface, and Yilmaz et al.…”

“…[147,148] A derivative of the Alvarez system is also presented where the two lenses are coaxially rotated rather than being parallelly moved, which is inspired by the Moiré lens. [149][150][151][152][153] Cui et al [151] proposed a rotationally tunable polarization-dependent varifocal metasurface, and Yilmaz et al [152] demonstrated a polarizationindependent varifocal metasurface. Subsequently, Guo et al [153] fabricated a 3.5× continuous varifocal meta-lens in the microwave band, with an improved N.A.…”

Electrically-Driven Zoom Metalens Based on Dynamically Controlling the Phase of Barium Titanate (BTO) Column Antennas

“…Some researchers combine the zooming method in traditional optics with metalens. For example, Ehsan Arbabi et al demonstrated tunable metasurface doublets based on micro-electromechanical systems [ 6 , 7 ], Nazmi Yilmaz et al proposed highly efficient rotationally tunable metasurface lens structures inspired by Moiré lenses [ 8 , 9 ] and Shane Colburn et al built a 1 cm aperture varifocal metalens system at 1550 nm wavelength inspired by an Alvarez lens [ 10 ]. Some researchers used unique optical modulation methods in the metasurfaces to realize the step zoom lens.…”