Generation of terahertz vector beams using dielectric metasurfaces via spin-decoupled phase control
Name:
[21928614 - Nanophotonics] Generation of terahertz vector beams using dielectric metasurfaces via spin-decoupled phase control.pdf
Size:
1.730Mb
Format:
PDF
Description:
Published version
Type
ArticleAuthors
Xu, YuehongZhang, Huifang
Li, Quan
Zhang, Xueqian
Xu, Quan
Zhang, Wentao
Hu, Cong
Zhang, Xixiang
Han, Jiaguang
Zhang, Weili
KAUST Department
Material Science and Engineering ProgramPhysical Science and Engineering (PSE) Division
KAUST Grant Number
URF-2950-CRG5CRF-2016-2950-RG5
CRF-2017-3427-CRG6)
Date
2020-06-30Online Publication Date
2020-06-30Print Publication Date
2020-06-25Submitted Date
2020-02-13Permanent link to this record
http://hdl.handle.net/10754/665358Metadata
Show full item recordAbstract
Cylindrical vector beams (CVBs), being a special kind of beams with spatially variant states of polarizations, are promising in photonics applications, including high-resolution imaging, plasmon excitation, optical trapping, and laser machining. Recently, generating CVBs using metasurfaces has drawn enormous interest owing to their highly designable, multifunctional, and integratable features. However, related studies remain unexplored in the terahertz regime. Here, a generic method for efficiently generating terahertz CVBs carrying orbital angular momentums (OAMs) is proposed and experimentally demonstrated using transmission-type spatial-variant dielectric metasurfaces, which is realized by designing the interference between the two circularly polarized transmission components. This method is based on spin-decoupled phase control allowed by simultaneously manipulating the dynamic phase and geometric phase of each structure, endowing more degree of freedom in designing the vector beams. Two types of metasurfaces which respectively generate polarization-dependent terahertz vector vortex beams (VVBs) and vector Bessel beams (VBBs) are experimentally characterized. The proposed method opens a new window to generate versatile vector beams, providing new capabilities in developing novel, compact, and high-performance devices applicable to broad electromagnetic spectral regimes.Citation
Xu, Y., Zhang, H., Li, Q., Zhang, X., Xu, Q., Zhang, W., … Zhang, W. (2020). Generation of terahertz vector beams using dielectric metasurfaces via spin-decoupled phase control. Nanophotonics, 9(10), 3393–3402. doi:10.1515/nanoph-2020-0112Sponsors
This research was funded by the National Natural Science Foundation of China (Grant Nos. 61605143, 61735012, 11974259, 61705167, 61875150, and 61420106006); Tianjin Municipal Fund for Distinguished Young Scholars (grant No. 18JCJQJC45600); Scientific Research Project of Tianjin Education Commission (Grant No. JWK1608); Start-up project of scientific research of Tianjin University of Technology and Education (Grant No. KYQD1718); Guangxi Key Laboratory of Automatic Detecting Technology and Instruments (YQ17203, YQ18205); King Abdullah University of Science and Technology, Office of Sponsored Research (Grand Nos. URF-2950-CRG5, CRF-2016-2950-RG5, and CRF-2017-3427-CRG6).Publisher
Walter de Gruyter GmbHJournal
NanophotonicsScopus Count
Except where otherwise noted, this item's license is described as This work is licensed under the Creative Commons Attribution 4.0 International License.
Related items
Showing items related by title, author, creator and subject.
-
Spin-Decoupled Multifunctional Metasurface for Asymmetric Polarization Generation(ACS Photonics, American Chemical Society (ACS), 2019-10-28) [Article]Integrating multiple functionalities into a single device is a striking field in metasurfaces. One promising aspect is polarization-dependent meta-devices enabled by simultaneous phase control over orthogonally polarized waves. Among these, Pancharatnam-Berry (PB) metasurfaces have drawn enormous interest owing to their natural and robust phase control ability over different circularly polarized waves. However, the phase responses are locked to be opposite with each other, resulting in interrelated functionalities under the circularly polarized incidence. Here, a generic designing method based on transmission-type dielectric metasurfaces is proposed in the terahertz regime, which breaks this relation by further incorporating dynamic phase with geometric phase, namely, spin-decoupled phase control method. We demonstrate this method by designing and characterizing an efficient multifunctional meta-grating, which splits different circularly polarized waves to asymmetric angles under normal incidences. More importantly, we promote this method by designing several multiplexed meta-gratings for applications of asymmetric polarization generation, which can convert arbitrary linearly polarized wave to two different linearly polarized waves with nearly equal strength and split them to asymmetric angles with a polarization-insensitive efficiency. The designing strategy proposed here shows an impressive robustness and a great flexibility for designing multifunctional metasurface-based devices and opens new avenues toward modulation of polarization states and the application of metasurfaces in beam steering and polarization multiplexing systems.
-
The Visual Object Tracking VOT2017 Challenge Results(2017 IEEE International Conference on Computer Vision Workshops (ICCVW), Institute of Electrical and Electronics Engineers (IEEE), 2018-01-22) [Conference Paper]The Visual Object Tracking challenge VOT2017 is the fifth annual tracker benchmarking activity organized by the VOT initiative. Results of 51 trackers are presented; many are state-of-the-art published at major computer vision conferences or journals in recent years. The evaluation included the standard VOT and other popular methodologies and a new 'real-time' experiment simulating a situation where a tracker processes images as if provided by a continuously running sensor. Performance of the tested trackers typically by far exceeds standard baselines. The source code for most of the trackers is publicly available from the VOT page. The VOT2017 goes beyond its predecessors by (i) improving the VOT public dataset and introducing a separate VOT2017 sequestered dataset, (ii) introducing a realtime tracking experiment and (iii) releasing a redesigned toolkit that supports complex experiments. The dataset, the evaluation kit and the results are publicly available at the challenge website1.
-
Unveiling of the energy storage mechanisms of multi -modified (Nb2O5@C)/rGO nanoarrays as anode for high voltage supercapacitors with formulated ionic liquid electrolytes(Electrochimica Acta, Elsevier BV, 2019-04-29) [Article]A better understanding of the energy-storage mechanisms in complex pseudocapacitive nanostructures is essential to improve the performances of nanohybrid supercapacitors. In this study, highly interface modified Nb2O5 nanoarrays, attached to graphene nanosheets, were carefully designed and synthesized. The electrochemical performances were evaluated in an organic electrolyte, a formulated ionic-liquid mixture electrolyte, and a nanocomposite ionogel electrolyte, respectively. The capacitive and faradaic storage contributions were assessed qualitatively in diverse electrolytes at various temperatures. The capacitive contribution in the ionic liquid electrolyte was found to rise with increasing temperature. A molecular dynamics simulation proved that the increased diffusion coefficient of large ions was much more pronounced than that of the small Li+ ions. A carefully optimized quasi-solid-state lithium ion capacitor, fabricated using a (Nb2O5@C)/rGO nanoarchitecture as the anode and an ionic liquid gel separator, delivered an energy density of 101 Wh kg−1 and a power density of 24 kW kg−1 at 60 °C. The efficient coupling between the nanohybrids and a complex ionogel electrolyte opens a new window for the rational design of high energy-density supercapacitors.
