Generation and Manipulation of Orbital Angular Momentum by All-Dielectric Metasurfaces

Abstract

We propose the design of a planar dielectric metasurface to overcome the ohmic loss and discrete phase profile of metallic metasurfaces. The proposed metasurface is composed of annular subwavelength gratings, which can be taken regard as a space-variant Pancharatnam-Berry phase optical element. Consequently, the OAM-carrying beams with topological charge ℓ =±2 is generated with the efficiency high up to 90 %. In addition, we demonstrate a method to produce fractional, quasi-focusing, and quasi-non-diffracting OAM-carrying beams by adopting appropriate width modulation of the annular gratings. The proposed metasurfaces offering superiorities in high efficiency, phase continuity, and manipulative diversity may have potential applications in integrated-photonics and optical communication system.

High-efficiency broadband vortex beam generator based on transmissive metasurface

“…In order to implement a vortex beam generator, a self-made Vivaldi antenna [48,49] is adopted as a feed source, which can radiate quasi-spherical waves with a broad bandwidth (7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18). The details of the structure, parameters and radiation pattern of the Vivaldi antenna can be found in Ref [48].…”

“…However, currently available devices face the challenges of the high profiles and low efficiencies. Nowadays, orbital angular momentum (OAM) vortex beam has attracted interesting attention owing to the spiral phase front carries orbital angular momentum [3][4][5][6][7][8][9][10]. The OAM vortex beam extends the communication capacity by its strictly orthogonal channel with different modes which carrying additional information [3].…”

Optimization on Plasmonic Lenses Based on Generation Efficiency of Surface Plasmon Polaritons at Metallic Nanoslit

“…Several efficient structures have been proposed and analysis on nanoslits has been done in some previous works [19][20][21][22][23][24]. In this paper, we mainly consider SPP generation efficiency under different compositions of nanoslit.…”

Deflection angle switching with a metasurface based on phase-change nanorods [Invited]

“…(1), the complex amplitudes of transmitted LCP light from each nanorod are dominantly determined by respective phase shifts for two orthogonal polarizations f and s. These respective phase shifts are determined by the length of the nanorod to the corresponding polarization direction [28] and the inherent refractive index of the material [29] . In addition, the exponential terms are determined by the angles θ u and θ l , following the principle of the Pancharatnam-Berry phase (geometric phase) [30][31][32] . Thus, the transmitted LCP light can have two different values E −σ;c and E −σ;a , depending on the size and angle of each of the two GST nanorods.…”