Abstract-Multiplexing THz Vortex Beams With a Single Diffractive 3-D Printed Len

Federico Machado, Przemysław Zagrajek, Vicente Ferrando, Juan A. Monsoriu, Walter D. Furlan

https://ieeexplore.ieee.org/document/8550797

We present a novel method for experimentally generating multiplexed THz vortex beams by using a single three-dimensional printed element that combines a set of radially distributed spiral phase plates, and a binary focusing Fresnel lens. With this element, we have experimentally demonstrated that THz multiplexing can be tailored to fit within a small space on an optical bench. Results are presented beside numerical simulations, demonstrating the robust nature of the experimental method.

Abstract-Multiplexing THz vortex beams with a single diffractive 3D printed lens

Federico Machado,  Przemyslaw Zagrajek, Vicente Ferrando, Juan A. A. Monsoriu,  Walter D. Furlan


https://ieeexplore.ieee.org/document/8550797

We present a novel method for experimentally generating multiplexed THz vortex beams by using a single 3D printed element that combines a set of radially distributed spiral phase plates, and a binary focusing Fresnel lens. With this element we have experimentally demonstrated that THz multiplexing can be tailored to fit within a small space on an optical bench. Results are presented beside numerical simulations, demonstrating the robust nature of the experimental method.

Abstract-Graphene-based tunable Imbert–Fedorov shifts and orbital angular momentum sidebands for reflected vortex beams in the terahertz region

Linqing Zhuo, Wenjin Long, Mengjiang Jiang, Wenguo Zhu, Heyuan Guan, Jieyuan Tang, Jianhui Yu, Huihui Lu, Jun Zhang, and Zhe Chen

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-43-12-2823

Upon reflection, a light beam embedded with 𝑚$m$-order orbital angular momentum (OAM) will undergo the Imbert–Fedorov (IF) shift, which induces OAM sidebands. The energies of the neighboring {−𝑚−1}$\{-m-1\}$ and {−𝑚+1}$\{-m+1\}$ sideband modes of the reflected beam are always equal. Controllable OAM sidebands are theoretically achieved by introducing a monolayer graphene in a three-layer structure composed of air, hexagonal boron nitride, and metal. By modulating the Fermi energy of graphene, the OAM-dependent IF shift can be tuned from positive to negative values, and the OAM sideband modes can be suppressed or enhanced, since the reflectivity for perpendicular and parallel polarizations vary with the Fermi energy. These findings provide an alternative method for the control of optical OAM in the terahertz region.

© 2018 Optical Society of America

Abstract-Terahertz circular Airy vortex beams

Changming Liu, Jinsong Liu, Liting Niu, Xuli Wei, Kejia Wang,  Zhengang Yang

https://www.nature.com/articles/s41598-017-04373-6

Vortex beams have received considerable research interests both in optical and millimeter-wave domain since its potential to be utilized in the wireless communications and novel imaging systems. Many well-known optical beams have been demonstrated to carry orbital angular momentum (OAM), such as Laguerre-Gaussian beams and high-order Bessel beams. Recently, the radially symmetric Airy beams that exhibit an abruptly autofocusing feature are also demonstrated to be capable of carrying OAM in the optical domain. However, due to the lack of efficient devices to manipulate terahertz (THz) beams, it could be a challenge to demonstrate the radially symmetric Airy beams in the THz domain. Here we demonstrate the THz circular Airy vortex beams (CAVBs) with a 0.3-THz continuous wave through 3D printing technology. Assisted by the rapidly 3D-printed phase plates, individual OAM states with topological charge l ranging from l = 0 to l = 3 and a multiplexed OAM state are successfully imposed into the radially symmetric Airy beams. We both numerically and experimentally investigate the propagation dynamics of the generated THz CAVBs, and the simulations agree well with the observations.

Abstract-Geometric phase shaping of terahertz vortex beams

Amalya Minasyan, Clément Trovato, Jérôme Degert, Eric Freysz, Etienne Brasselet, and Emmanuel Abraham

https://www.osapublishing.org/ol/abstract.cfm?uri=ol-42-1-41

We propose a topological beam-shaping strategy of terahertz (THz) beams using geometric phase elements made of space-variant birefringent slabs. Quasi-monochromatic THz vortex beams are produced and characterized both in amplitude and phase from the reconstructed real-time two-dimensional imaging of the electric field. Nonseparable superpositions of such vortex beams are also obtained and characterized by two-dimensional polarimetric analysis. These results emphasize the versatility of the spin-orbit electromagnetic toolbox to prepare on-demand structured light endowed with polarization-controlled orbital angular momentum content in the THz domain, which should find many uses in future THz technologies.

© 2016 Optical Society of America

Full Article  |  PDF Article