Generation of orbital angular momentum and focused beams with tri-layer medium metamaterial*

Sun, Zhichao; Yan, Ming; Xu, Bo

doi:10.1088/1674-1056/abab79

Cited by 12 publications

(7 citation statements)

References 35 publications

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“…[9] The wavefront of the OAM beam has a helical phase and its electric field complex amplitude contains a term of exp [iℓθ ], where ℓ can be an arbitrary integer named topological charge or azimuthal index, representing the number of 2π phase shifts across the beam, and θ is the azimuthal angle. The OAM beams of different modes are orthogonal to each other, [10][11][12][13] which supports efficient multiplexing of OAM and provides a new degree of freedom for expanding the capacity of the UWOC system. [14] In order to improve the OAM multiplexing efficiency of a UWOC system, the detection and recognition of OAM modes are crucial.…”

Section: Introductionmentioning

confidence: 99%

Diffraction deep neural network based orbital angular momentum mode recognition scheme in oceanic turbulence

et al. 2023

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Orbital angular momentum (OAM) has the characteristics of mutual orthogonality between modes, and been applied to underwater wireless optical communication (UWOC) system to increase the channel capacity. In this work, we propose a diffractive deep neural network (DDNN) based OAM mode recognition scheme, where the DDNN is trained to capture the features of the intensity distribution of the OAM modes and output the corresponding azimuthal indices and radial indices. The results show that the proposed scheme can recognize the azimuthal indices and radial indices of the OAM modes accurately and quickly. In addition, the proposed scheme can resist weak oceanic turbulence (OT), and exhibit excellent ability to recognize OAM modes in a strong OT environment. The DDNN-based OAM mode recognition scheme has potential application value to UWOC system.

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Section: Introductionmentioning

confidence: 99%

Diffraction deep neural network based orbital angular momentum mode recognition scheme in oceanic turbulence

et al. 2023

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“…The conclusions are beneficial to the OAM-based communication, optical metrology, and imaging by varying the initial non-uniform polarizations and vortex cores. [22][23][24]…”

Section: Introductionmentioning

confidence: 99%

Asymmetrical spiral spectra and orbital angular momentum density of non-uniformly polarized vortex beams in uniaxial crystals

Shu¹,

Cheng²,

Liao³

et al. 2023

Chinese Phys. B

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To explore the effect of non-uniform polarization on orbital angular momentum (OAM) in anisotropic media, we investigate the evolution of the spiral spectra and OAM densities of non-uniformly polarized vortex (NUPV) beams in uniaxial crystals propagating orthogonal to the optical axis, where the case of uniformly polarized vortex (UPV) beams with left-handed elliptical polarization is also investigated. At the input plane, the NUPV beams present their spiral spectra of m concentrated at m=l±1 rather than m=l, and reveal the relation between topological charge l, mode of spiral spectra m and the power weight value R m expressed by $l = \sum\limits_{m = - \infty }^\infty {m{R_m}} $. The relation $l = \sum\limits_{m = - \infty }^\infty {m{R_m}} $ is still satisfied for UPV beams in uniaxially anisotropic crystals, whereas for NUPV beams their relations are no longer valid owing to non-uniform polarization. Furthermore, the analysis indicates that the asymmetrical distribution of power weight of spiral spectra and the non-zero value in the sum of longitudinal OAM densities originate from the initial non-uniform polarization and anisotropy in uniaxial crystals rather than topological charges. In addition, the relation between spiral spectrum and longitudinal OAM density is numerically discussed. This work may provide an avenue for OAM-based communications, optical metrology and imaging by varying the initial non-uniform polarization.

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“…[4] At present, researchers have proposed a variety of antennas for generating OAM waves, such as spiral phase plates, [9] spiral reflectors, [10] circular arrays, [11] traveling wave antennas, [12] dielectric reso-nant antennas, [13] and metasurfaces. [14][15][16][17][18][19][20] In particular, there are two types of metasurfaces: reflective metasurfaces [21] and transmitted metasurfaces. [22,23] Compared with reflective metasurfaces, transmitted metasurfaces can reduce blockage of feed antennae.…”

Section: Introductionmentioning

confidence: 99%

Design of cylindrical conformal transmitted metasurface for orbital angular momentum vortex wave generation

Fu¹,

Yu²,

Kou³

et al. 2022

Chinese Phys. B

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In this paper, a cylindrical conformal transmitted metasurface for orbital angular momentum vortex wave generation is proposed. Formulas for calculating the phase distributions of cylindrical conformal transmitted metasurface is presented. A prototype of the proposed conformal transmitted metasurface is designed, fabricated and measured. Measured results shows that the proposed conformal transmitted metasurface can effectively generate vortex waves, which verifies the effectiveness of our method. The proposed method may pave the way for vortex wave generation with cylindrical conformal device.

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Generation of orbital angular momentum and focused beams with tri-layer medium metamaterial*

Cited by 12 publications

References 35 publications

Diffraction deep neural network based orbital angular momentum mode recognition scheme in oceanic turbulence

Diffraction deep neural network based orbital angular momentum mode recognition scheme in oceanic turbulence

Asymmetrical spiral spectra and orbital angular momentum density of non-uniformly polarized vortex beams in uniaxial crystals

Design of cylindrical conformal transmitted metasurface for orbital angular momentum vortex wave generation

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